Be ready to ship with ASP.NET 5.0

• Rename the public API to contain “Microsoft”: #193
  • Long tail of work in samples, quickstarts, docs, …
  • Let’s have the current methods in a different file, with an [Obsolete:warning] attribute
• Have the code reviewed by Chris Ross: starting next week
• Add a .NET 5.0 target
  • This impacts our dev environment
• Support nullable types (See asp.net #22656)
• Update the templates to support .NET 5.0 as well

Included in 0.2.0-preview release