Test two windows drawing GL with different contexts.
Test two windows drawing GL with different contexts.

theblacklion/pyglet,theblacklion/pyglet,oktayacikalin/pyglet,adamlwgriffiths/Pyglet,oktayacikalin/pyglet,mammadori/pyglet,niklaskorz/pyglet,adamlwgriffiths/Pyglet,niklaskorz/pyglet,mammadori/pyglet,theblacklion/pyglet,oktayacikalin/pyglet,niklaskorz/pyglet,oktayacikalin/pyglet,seeminglee/pyglet64,adamlwgriffiths/Pyglet,mammadori/pyglet,niklaskorz/pyglet,seeminglee/pyglet64,theblacklion/pyglet,theblacklion/pyglet,adamlwgriffiths/Pyglet,oktayacikalin/pyglet,mammadori/pyglet,seeminglee/pyglet64