All WinRT projects have been merged into a single directory, "VisualC-WinRT",
with platform-specific variants in subdirectories off of it.  WinRT development
currently requires muliple project types, one for Windows 8.0, a second for
Windows Phone 8.0, and a third, possibly a fourth, for Windows 8.1 and/or
Windows Phone 8.1 targets.

The first two, for Windows 8.0 and Windows Phone 8.0 targets, are now in place,
inside "WinRT80_VS2012" and "WinPhone80_VS2012" subdirectories.  Both require
the VS2012 toolchain(s).

Projects that use SDL_image/WinRT will need to have existing references to
SDL_image, and its dependencies libraries, removed and then re-added.  This can
be done by:
1. removing the MSVC projects for SDL_image, libpng, jpeg, and zlib (for WinRT)
2. re-added the MSVC projects for SDL_image, libpng, jpeg, and zlib (for WinRT)
3. right-clickong on the app, or projects that use those libraries, choosing
References, removing the references to any of these projects (they'll likely
be highlighted with an exclamation mark), then re-adding them

TODO:
- add support for Windows 8.1 and Windows Phone 8.1 targets, using
Microsoft's new "Universal" app support, if possible.  These will be added to
a new subdirectory, or subdirectories (if more than one sets of projects are
needed, hopefully not), of "VisualC-WinRT".
- add a README.txt file inside VisualC-WinRT that explains which directories
are used for which targets, along with some basic setup info