Made changes to how ScaleoutSubscription gets messages.
- Encapsulate pulling mappings from streams in an enumerator.
- Use nullable ulong for next cursors. Only update the ones that
  are non null.
Updated the js files
Merge branch 'release' into dev

Conflicts:
	samples/Microsoft.AspNet.SignalR.Hosting.AspNet.Samples/Scripts/jquery.signalR.min.js
	samples/Microsoft.AspNet.SignalR.LoadTestHarness/Scripts/jquery.signalR.min.js