Initiate /start request after a transport is selected in the JS client

- This is how the .NET client already behaves

#3104
Bump version to 2.1.1
.NET Client: Dispatch failed hub invocation callbacks on reconnecting
- #3101
Merge branch 'release' into dev

Conflicts:
	build/Microsoft.AspNet.SignalR.versions.targets
Make HubConnection.cs in client use new Catch overload
- Updated xunit
- #3101