Add OpenGL ES 3.1 context creation

Add OpenGL ES 3.1 context creation to allow context creation of OpenGL 3.1 in desktop OpenGL.

Same way as we have OpenGL ES 2.0 and 3.0 context creation in desktop OpenGL already.

Last time I checked, context creation was not specified in the OpenGL® specification.

OpenGL® ES is not desktop OpenGL®. You are requesting the platform specific API to create a context for something different and I’m sure it shouldn’t be too much of a problem to add that capabillity in the platform dependend APIs.