Draft attempt at creating WinRT version.

Code compiles, I make no other guarantees at this point.
Draft attempt at WinRT version now compiles in release mode too :P
Sign WinRT assembly.
Change output path for universal WinRT library in release mode.
Add WINRT assembly in appropriate nuget folder.
Update winrt binary.
Rebuild and update nuget package.

Rebuild all libraries, fix up output paths etc. for winrt library,
rebuild nuget package.