- Changed IHubConnectionContext and friends to be generic.
- Hub by default is Hub<IClientProxy>. We'll enable dynamic and arbitrary TClients in another commit.
- Moved the IHubConnectionContext implementation out of HubEndPoint
- Added IHubContext to allow getting at the publish side of things without
being in side the hub. The HubEndPoint now injects this as well.
- HubContext has the implementation of the IHubConnectionContext
- Moved ISignalRBuilder and SignalRBuilder into their own files