SPV compression: Remove file/path manipulation stuff, setting up for that to...

SPV compression: Remove file/path manipulation stuff, setting up for that to be a separate tool.  Added copyright messages as well.


git-svn-id: https://cvs.khronos.org/svn/repos/ogl/trunk/ecosystem/public/sdk/tools/glslang@31201 e7fa87d3-cd2b-0410-9028-fcbf551c1848