Make `Graphics` submit all calls instantly
Make `Graphics` submit all calls instantly

There is no reason to wait, we are on the same thread as the device.

Closes #299

alexcrichton/gfx,JohnColanduoni/gfx,JohnColanduoni/gfx,tanderegg/gfx,ColinKinloch/gfx,davll/gfx,aepsil0n/gfx-rs,red75prime/gfx,gfx-rs/gfx-rs,tanderegg/gfx,bvssvni/gfx-rs,Bastacyclop/gfx,tempbottle/gfx,sectopod/gfx-rs,ColinKinloch/gfx,mitchmindtree/gfx-rs