Fixed a crash on Windows Phone 8 that occurred after rotating a device

This changeset prevents IDXGISwapChain::ResizeBuffers from being invoked on
Windows Phone 8, a function that isn't available on the platform (but is
available on other Windows platforms).  The call would fail, which ultimately
led to a crash.

This changeset also attempts to make sure that the D3D11 swap chain is created
at the correct size, when using Windows Phone 8.

Still TODO: make sure rotation-querying works across relevant Windows
platforms (that support Direct3D 11.x).
Fixed broken rotation detection routines on WinRT

Rotation detection and handling should now work across all, publicly-released,
WinRT-based platforms (Windows 8.0, Windows 8.1, and Windows Phone 8.0).