Added configuration files for generation VS2012 solutions

Added configuration files for generating VS2012 solutions for Full, Empty, Full PhysX and Empty PhysX. By default platform toolkit is set to "Visual Studio 2012 - Windows XP (v110_xp)". Maybe others need VS2012 Update 1, but it shouldn't be problem to set that by default to "Visual Studio 2012 (v110)" if needed. Safe Exception Handlers is set by default on NO (/SAFESEH:NO) and hardcored DXSDK library files is replaced with props files for both x86 and x86_64 configuration on VS2012 solution files.