BGE code cleanup: Removing RAS_GLExtensionManager.

This class did nothing but print out extensions if they were found.
Instead, the code from bge.logic.PrintGLInfo() is now printed as the
Rasterizer is initialized. This gives better information, and it removes
some GL code from KX_PythonInit.cpp (the PrintGLInfo method now calls
the Rasterizer to print the information).

Differential Revision: https://developer.blender.org/D438

source/gameengine/VideoTexture/blendVideoTex.cpp

@@ -32,8 +32,6 @@
 
 #include "KX_PythonInit.h"
 
-#include <RAS_GLExtensionManager.h>
-
 #include <RAS_IPolygonMaterial.h>
 
 //Old API