Add HW bounding Box support to d3d backend
Added support test for bbox and some naming corrections
small spacing fixes
use SAFE_RELEASE to make code cleaner
Adds LLVM version check to cmake.

We require LLVM 3.4 minimum, so if the user has something older make sure to not attempt compiling.
Fixes issues #7858 and #7906.
Enables stereo rendering with OpenGL ES 3.1 + AEP.

If the host device supports GLES 3.1 and AEP we can have stereo rendering.
Just need to make sure to grab the correct function pointer that GL_EXT_geometry_shader provides, and enable AEP in the shaders.

We can't just check if AEP is in the extension list for support because Qualcomm has failed once more.
With the Nexus 6 it reports support for AEP but doesn't support OpenGL ES 3.1, which is an impossible combination.
From reports on their forum it seems that attempting to use any AEP things results in nothing happening, seems like a stub implementation.
Merge pull request #1664 from Sonicadvance1/GLES3_stereo

Enables stereo rendering with OpenGL ES 3.1 + AEP.
Merge pull request #1667 from Sonicadvance1/check_llvm_version

Adds LLVM version check to cmake.
Jit64: clean up casts in memory operands
Merge pull request #1668 from Tilka/memop_cleanup

Jit64: clean up casts in memory operands
spaces cleanup
Merge pull request #1657 from Tinob/master

Add HW bounding Box support to d3d backend
Specified where to find CACHE_REVISION
Merge pull request #1673 from Stevoisiak/Cache_Revision-Comment

Specified where to find CACHE_REVISION