Add :
-> clCreateContext
-> clCreateContextFromType
-> clGetContextInfo
-> clReleaseContext

Modify :
-> catchError : for the simple error exception (not WebCLException) return -1
-> add getExtension KHR_GL_SHARING / KHR_FP64 / KHR_FP16
-> add getInfo DEVICE_PREFERRED_VECTOR_WIDTH_DOUBLE / DEVICE_PREFERRED_VECTOR_WIDTH_HALF