Try adding support for ARB_instanced_arrays

Convert the colors array back to unsigned char, try adding support
for ARB_instanced_arays. Fix up wireframe and picking for when
the fast path is being used. Previously that would fail.

Change-Id: Iada6b55f01ca7f2c3f68362f3e7da7e99fa15eeb
Merge topic 'try_glyph_extension' into master

23ceef01 Try adding support for ARB_instanced_arrays