17.2.1.500-1

• Updated Mesa3D to 17.2.1;
• Added OpenSWR support to deployment utility;
• Built Mesa3D with LLVM 5.0 using a patch which adds support for it;
• Built LLVM with Visual Studio 2017 v15.3.4;
• Mesa3D build: updated Python to 2.7.14;
• Build script: Always use a compiler that matches host architecture; previously CMake with MsBuild was always using 32-bit compiler throwing a warning in the process; ninja and Scons were using the compiler matching the build target architecture;
• Build script: Support downloading Mesa code using Git, apply LLVM 5.0 support and S3TC texture cache enabling patches automatically using Git when possible;
• Deployment utility and build script: 32-bit OpenSWR is unsupported;
• Build script: Attempted restore of Visual Studio 2015 support; Visual Studio 2015 compatibility toolset for VS2017 should work fine; Visual Studio 2015 default toolset is untested;
• Build script documentation: switch Mesa download link to HTTPS, info about LLVM 5.0 support auto-patch, S3TC texture cache auto-patching, unsupported 32-bit OpenSWR and build script wizard updates.