Add VS2013 build files

This does not compile yet, but commit the files to save others the work
of creating the framework.

Known issues:
- Some editor-specific files do not find their headers due to missing
  AdditionalIncludeDirectories
- VS2013.2 picks incorrect variadic template overloads.  VS2013.3 might
  do better.
- VS2013.2 C preprocessor mishandles C99 __VA_ARGS__ usage