* Update HubProtocol.md
Updated the code sample in the protocol doc to reflect the actual programming API
* Update src/SignalR/docs/specs/HubProtocol.md
Co-Authored-By: Brennan <brecon@microsoft.com>
Part of #4246
Changes:
* Update source code layout to follow the new conventions for this repo
* Update project files to use `<Reference>`
* Update targets to build NPM packages
* Update BuildTools to support custom 'restore' and 'test' targets