Merge changes I66085c30,Ic9b3be9f,Icc6b23ab,I359a9511,I11a7394e,Ic8bcd03e,I40834d6f...

* changes:
  Subclass GLES30 from GLES20, @Deprecate GL_STENCIL_INDEX
  Special-case glGetActiveUniformBlockName
  Special-case glGetStringi
  Special-case glMapBufferRange
  Special-case glGetBufferPointerv
  Special-case glGetUniformIndices
  Special-case glGetTransformFeedbackVarying
  Special-case glTransformFeedbackVaryings
  Add buffer object versions of several functions
  Add *int64 and GLsync types and related functions
  Add ES3 functions and constants, difficult ones commented out
  Support "const GLChar*" and "const GLenum*" types
  Minor changes to ES3 functions inherited from ES2
  Generate GLES30 class, just a clone of GLES20 for now