Update version to 2.1.2
Fix SQL duplicate messages issue:
- Ensure the state is reset at the beginning of the receive loop
- Added more tracing to detect unexpected states in the ObservableDbOperation state machine
- #2988
Added unit tests
SmallBigData - allowing messages longer than 32766 characters

Fixes work item #3040

Non .NET Framework 4 clients used the FormUrlEncodedContent class to escape messages sent by clients. This limited the length of the message to 32766 characters. For longer the client would fail with the invalid uri exception saying "The Uri string is too long". The messages are not actually Uris so we don't care about the length. The fix is to use a custom UrlEncoder we already have which is functionally equivalent to Uri.EscapeDataString() but will not throw if message is longer than 32766 characters.
Update version in hub.js in sample project
Merge branch 'release' into dev
Fixed the Hub Auth portion of the Sample project

- By calling MapSignalR later we can ensure SignalR runs after auth
  middleware and HttpApplication.AuthenticateRequest.

#3152