Remove the remaining bits of deprecated GL usage

The drawing is now completely shader based, which makes away
with all usage of the depracted matrix stack. This also allows
us to do things like simple translations and texture coordinate
translation directly instead of doing everything indirectly
through matrices.

Fixed vertex attributes ('vertexPointer()' etc) are also
replaced with user defined attribute arrays.

src/glstate.h

@@ -124,13 +124,6 @@ public:
 	GLBlendMode blendMode;
 	GLViewport viewport;
 
-	/* These functions pushSet/pop both the viewport
-	 * and a glOrtho projection matrix.
-	 * Useful for setting up rendering to FBOs of differing sizes */
-	void setViewport(int width, int height);
-	void pushSetViewport(int width, int height);
-	void popViewport();
-
 	struct Caps
 	{
 		int maxTexSize;