Minor optimization in index_buffer::Index
Minor optimization in index_buffer::Index

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