Merge in eglQueryString changes

Host components now buildable in their correct locations (although stil using CMake). Use build.bat in package root. Note holdingarea build no longer works and everything except llvm will be removed soon. Fix ups to references to components moved to vghwinterface. Move package common headers up to pacakge level inc directory.

Move GLES20 source into standard locations Move Khronos headers into their respective components, to be exported by each. Remove hostthreadadapter as nothing outside of the vghwapiwrapper, which now contains the code, needs it