* Updated signalr script tag (#14810)
The location of signalr.js was incorrect according to Target Location set
up when Client-Side Library was added earlier in tutorial.
* changed the location for vscode libman install (#14810)
* Update SignalR tutorial to 3.0 - startup.cs - addtional screenshots
* moved moniker to metadata only
* added dotnet watch run for VSCode to fix for 9488 while here.
Luke Latham
Rick Anderson
Max Lefebvre
Wade Pickett
Tom Dykstra