Add a new shader-versioning infrastructure capable of handling multiple profiles, desktop/ES, many versions, features coming and going in different versions across different profiles, and extensions.  

NB: *Use* of this infrastructure is so far only skeletal.

Fixed a few typos and minor issues along the way.


git-svn-id: https://cvs.khronos.org/svn/repos/ogl/trunk/ecosystem/public/sdk/tools/glslang@19951 e7fa87d3-cd2b-0410-9028-fcbf551c1848