Setting output directories for WinPhone builds to fix build errors.
Don't output debugdir for WinRT builds, since it messes up the emulator.
Adding WinRT platform function and setting it to use multithreaded rendering.
Adding specialized codepaths for swapchain creation on WinRT, since it requires DXGI 1.3.
WinRT builds needs to static link against the D3D11 and DXGI libs.
Adding WinRT entrypoint for examples.