* Refs #4720 Removing warning message (#425)

* Creating a new PDP superclass

* BuiltinProtocols now references a PDP superclass

* Discovery-Server client implementation fulfill

* PDPServer renamed to PDPClient

* squash of all schema, parser and transport modifications

* XMLParser update to new profiles

* XMLParser update to new profiles

* Modified RemoteServerAttributes xml schema to enforce that:

* at least one multicast or unicast locator list MUST appear.
* the locator list may appear in any order

<xs:complexType name="RemoteServerAttributes">
	<xs:choice>
		<xs:sequence>
			<xs:element name="metatrafficUnicastLocatorList" type="locatorListType" minOccurs="1" />
			<xs:element name="metatrafficMulticastLocatorList" type="locatorListType" minOccurs="0" />
		</xs:sequence>
		<xs:sequence>
			<xs:element name="metatrafficMulticastLocatorList" type="locatorListType" minOccurs="1" />
			<xs:element name="metatrafficUnicastLocatorList" type="locatorListType" minOccurs="0" />
		</xs:sequence>
	</xs:choice>
	<xs:attribute name="Prefix" type="guid" use="required"/>
</xs:complexType>

* StatefulReader modifications to allow unknown clients discovery

* EDPSimple extensive modifications to allow TRANSIENT EDP Writers

* Created a EDPListener ancestor for EDPSubListener and EDPPubListener

* Adding new dll exports to allow external discovery handling

* EDP matching correction

* PDPListener Server List update corrections

* PDP::notifyAboveRemoteEndpoints promote to virtual in order to solve WLP matching problem

* Updated StatefulWriter to allow acknowledge assessment

* PDPListener error correction. New method added to PDP.

* corrected PDP match problem

* Modified BuiltinProtocols to use a class factory for EXTERNAL discovery

* Workaround for the endpoint.remoteLocatorList in PDPClient and EDPSimple

* StatefulReader workaround to prevent clients message exchange with nonserver participants

* Extended PDPType_t to BACKUP

* DSClientEvent must be restart_timer() after creation to make it roll downhill

* Add PDP mutex protection to builtin protocols server list to avoid sync problems.

* Server list was accessed without using references with nefandous consequences.

* matched_reader_add doesn't need a remoteLocatorList to work. Removed.

* DSClientEvent made continuos announcement despite all servers were discovered. Now it stops when all are discovered and starts again when any of them vanishes.

* minor aesthetic changes in PDPClient methods

* Exporting message sending functionality to make it available to discovery-server. This changes would be undone when discovery-server becomes incorporated into the library.

* There is a synchronization problem. PDP base implementation assumes that only m_participantProxies keeps references to ParticipantProxyData pointers.
 For example in PDP::removeRemoteParticipant only the access to m_participantProxies is mutex protected. The ParticipantProxyData objects were destroyed in a non protected code. PDPServer::match_all_clients_EDP_endpoints() run parallel to PDP::removeRemoteParticipant and use pData just destroyed. In order to solve this problem we must make not only the m_participantProxies access but also the specific pointers mutex protected.

* PDP, PDPClient and PDPServer modified to make participant removal independent of the trigger cause (DATA msg received, lease duration timeout or future mechanisms).

* Correcting schema type. discoverServerList -> discoveryServerList

* Extend RemoteServerAttributes with a method to return its associated participant GUID_t.

* Extended History API with reverse iterator to accelerate searching.

* PDPClientr::announceParticipantState modified to use the cache sample_identity to avoid history duplications.

* Modified PDP::announceParticipantState to allow all discovery metatraffic to be keyed in WriteParams.

* Added EDPClient : public EDPSimple in order to key-sign the newly created DATA(w|r)

* Correct EDP and PDP sequencing of the CacheChanges

* Solved PDP callback synchronization issues.

* Refs #5021 Fixing compilation issues on Linux. Removed debug folders.

* Refs #5021 Fixed XMLParserTests' xml profile file.

* In order to make easier Colcon use in discovery server all server funcionality was integrated into fast-RTPS library.

* Refs #5021 Removed C++14 features. Fixed initialization order warning.

* Refs #5021 Applied asio < 1.12 patch.

* synchronization problem solved. PDP mutex must be used only to guarantee atomic access to discovery database.

* It seems to be a lease duration event - participant destruction race condition overlook till now. I should ask fastRTPS team.

* Detected 2 logical errors in PDPServer implementation:
- A server shouldn't match another server's clients. Because a client would only match one server. DATA(p) contain information that helps us to manage this case.
- PDPServer::removeParticipantForEDPMatch was passed a wrong argument (_p2match keeps references to ParticipantProxyData manage by PDP).
Both errors are now corrected.

*  The only modification I introduced was when the DServerEvent thread is awakened:

  - bool PDPServer::initPDP(RTPSParticipantImpl* part) - At server creation (to try announce itself to other servers)
  - void PDPServer::queueParticipantForEDPMatch(const ParticipantProxyData * pdata) - when a new client announces itself (to match its endpoints)
  - bool PDPServer::removeRemoteParticipant(GUID_t& partGUID) - when a client is removed (to unmatch and trim the PDP and EDP caches)

* DServerEvent must be awaked also when a publisher or subscriber is removed whenever trim is not successful at once.

* Update the client and server event period to accelerate matching and reduce discovery times.

* Client announcement must be replace because under certain settings prevents periodical HEARTBEAT. I copy the PDPServer announcement strategy.

* Updated several attribute structures to avoid warnings on some examples compilation.

* Refs #5021 Linux warnings.

* comments update

* solved VS class view issue. Lack of some headers inclusion.

* changing client & server announcement strategy on participant shutdown

* updating client & server announcement strategy on participant shutdown to reduce RTPSReader impact

* Refs #5235 Added operator>> to EntityId

* Updated lease duration strategy for client-server environment

* Lease Duration mechanism updated for client-server framework

* lease Duration synch problem solved

* Solved simple discovery initialization issues. DATA(p) processing may overlap the initialization and cause lost of EDP discovery data.

* removing warnings on test due library header dependencies changes

* Gasco's code review comment's applied

* Sources modified to prevent build errors. Note that StatefulWriter API changes forces a refactorization of the announcement mechanism in PDP client and server. Pending to solve blackbox test issues.

* Blackbox TCP test issues solved.

* xml parsing tests and examples corrected

* Solving some bugs on server PDP initialization

* Discovery issues on TCP transport solved. All clients have now a TCP listening port if using TCP transport.

* Solve discovery server issue: TCP client addresses conflict on different processes.

* solved linux connection issues on tpc

* Solved little merge conflicts introduced above original merge commit

* Solving serveral warnings highlighted by MAC compiler

* amend to the last commit

* Discovery service update. Now is mandatory that a TCP client defines a listening port. It was decided by quorum that dynamic allocation of tcp listening ports for clients was error prone is some scenarios.

* solving minor MAC compilation issues

* PDPType enum is now more properly called DiscoveryProtocol

* BuiltinAttributes has now al discovery info grouped into a DiscoverySettings object

* Solved some PDPClient and PDPServer announcement issues. Mutex protect the change sequence number and atomic access to server and client lists.

* Rationalization of PDPServer mutex protection of member collections and EDP member collections.

* Solved synchronization issue in server's handling of DATA(p[UD]) messages.

* Solved synchronization issue in server's handling of DATA(p[UD]) messages.

* std::make_unique is not availabe on C++11

* Add a warning on the properly lock order (PDP Writer and PDP mutexes) for announceParticipantState

* Solved merge conflicts (mainly liveliness) with the current commit of develop (26b1f56)

* BuiltinAttributes leaseDuration has now been moved into DiscoverySettings

* DiscoverySettings operator== correction