Merge remote-tracking branch 'SignalR/rybrande/release21ToSrc' into rybrande/Mondo2.1

src/SignalR/.gitignore

src/SignalR/Directory.Build.props

src/SignalR/Directory.Build.targets

src/SignalR/NuGetPackageVerifier.json

src/SignalR/README.md

src/SignalR/SignalR.sln

src/SignalR/THIRD-PARTY-NOTICES

...nalR/benchmarkapps/BenchmarkServer/BenchmarkServer.csproj

src/SignalR/benchmarkapps/BenchmarkServer/Hubs/EchoHub.cs

src/SignalR/benchmarkapps/BenchmarkServer/Program.cs

src/SignalR/benchmarkapps/BenchmarkServer/README.md

src/SignalR/benchmarkapps/BenchmarkServer/Startup.cs

src/SignalR/benchmarkapps/BenchmarkServer/signalr.json

src/SignalR/benchmarkapps/Crankier/Agent.cs

...gnalR/benchmarkapps/Crankier/AgentHeartbeatInformation.cs

src/SignalR/benchmarkapps/Crankier/AgentReceiver.cs

src/SignalR/benchmarkapps/Crankier/AgentSender.cs

src/SignalR/benchmarkapps/Crankier/AgentWorker.cs

src/SignalR/benchmarkapps/Crankier/Client.cs

src/SignalR/benchmarkapps/Crankier/Commands/AgentCommand.cs