Wire up SignalR websockets via new HttpAbstractions
- Removed the OwinWebSocketHandler as this will be pushed further down the stack
- Simplified websocket object model since we don't need to handle websocket
 callbacks anymore we can directly handle it inline.
Use pool of buffers when writing outgoing responses
- Use IMemoryPool and MemoryPool impl from Kestrel to write outgoing
responses for all transports.
- Removed BinaryTextWriter.cs and BufferTextWriter.cs implementations
 and replaced them with MemoryPoolTextWriter and BinaryMemoryPoolTextWriter
 impl.
- Simplified IWebSocket and WebSocketTransport by only allowing
  ArraySegment<byte> to be sent. Also Removed SendChunk and
  Flush methods since we'll always send a single chunk.
- Use preallocated byte[] for keep alive sends and initialize sends for each
  transport.
- Updated sample to allow switching transport in the query string. Ported
 signalr.samples.js from the existing SignalR/SignalR repository.
- Verified on existing SignalR stack that this doesn't regress performance
with the existing pool sizes compared to the existing impl.
Updated kproj file
Fixed transport types enum
- WebSockets can't be 0 otherwise it's always enabled
Rename project file to Microsoft.AspNet.SignalR.Server
Added first set of tests
- Removed WebsocketTransportFacts since they are no longer relevant.
- Adding extra IMemoryPool parameter to ForeverTransportFacts
Fixed default MessageBusOptions
Added ScaleOutMessageBusFacts
Added SubscriptionFacts
Added ScaleoutStreamManagerFacts
Added ScaleoutStreamFacts
Added LongPollingTransportFacts
Added StringMinifierFacts and TaskQueueFacts
Added PersistentConnectionFacts and PersistentResponseFacts
Added ArrayTextReaderFacts, CursorFacts and SignalROptionsFacts
Added DefaultActionResolverFacts, DefaultHubResolverFacts and GroupManagerFacts
Added WebSocketFacts
Added JsonFacts and JsonSerializerExtensionFacts
Added ForeverFrameTransportEscapesTags
- Skipped tests that assume regular ajax sends
 would be escaped temporarily.
Added more Hub tests