Fix using unsupported functions for GL 3.0 and 3.1 contexts
Fix using unsupported functions for GL 3.0 and 3.1 contexts

tomaka/glium,cpjreynolds/glium,acolley/glium,glium/glium,msiglreith/glium,bvssvni/glium,sdotz/glium,binsoftware/glium,rozaliev/glium,caldwell/glium,TyOverby/glium,christopheraugustus/glium,carbidegames/glium,nicokoch/glium