- Removed DXGI_1_2_FORMATS and USE_XNAMATH control defines
- Deleted *Desktop_2010_SDK81.* project files, updated *Desktop_2010.* project files to use Windows 8.1 SDK
Otherwise they just get a default name of eg. vs100.pdb, which causes conflicts for who people want to copy the output .lib + .pdb into a common folder that also contains the outputs from other projects.