WinRT : UWP port for Windows 10

[MoeMod]

FWGS/xash3d#408

Current Status:
Almost everything works except mouse input.

[HowToDoThis]

Known Issues:

• Mouse Problems
• Startup music sounds noisy
• Touch keyboard on mainui shows and collapses immediately
• Random crash when IME enabled (?)
• Window size / fullscreen / maximized not remembered
• Added soon if founded new or reported by users

[MoeMod]

almost done.