Patch Emscripten for webcl compatibility :

Add header OpenCL & cuda
Add library_opencl.js & library_cuda.js

Modify emcc for support of validator parameter
Modify modules.js for add the new library
Modify file_packager.py for support of webcl-validator
Modify settings for add some settings fro library_opencl.js
Modify library_gl for support of VAO extension when LEGACY_GL_EMULATION=0