…org (#727)

Cleaned up navigation after v2.1.
Made navigation through menus and docs consistent as to when to remain in an extension or to force to basic schema.org.  Included making schemas.html into a template.

Also maintains the http/https state through a user session.
Corrected thread based caching of global variables errors that were introduced with extensions - reset temporary fix of threadsafe=false in app.yaml.

Introduced a /_siteDebug page to monitor cache usage and settings etc.

Issues:
(#429) - Completing the initial extensions model
(#732) - Docs links for menus now go to base url
(#716) - Preparing ground by at least being in session consistent

… on a sentence boundary to a sensible length - curently 200 chars)

…comment.

Removed erronious characters from ItemList example

Cleaned up remaining navigation issues after v2.1.

…ey are classes (#662)

Also fixed couple of domain assersions on Vehicle that replicated from parent class

…& purchaseDate.

Changed relevent tests for this to expectedfailure and just output warning.
Collect warnings to output at end of test run.

§

release notes.

Unit test for domain & range for valid name and type…

Issue #688: Added DataFeed and DataFeedItem including examples and

Issue #687: Added Barcode as a subtype of ImageObject.

We don't yet indicate which extension/core each type lives in.

Introduced json.dump() to encode strings in json output for tree.jsonld

…nto sdo-phobos

From example by @frankieroberto
From issue #445

Create sdo-exhibitionevent-examples.txt

…nto sdo-phobos

Mistakenly earlier version was from /version/ (giving a table of contents only).