Fix GL context leak by destroying it before the window
Fix GL context leak by destroying it before the window

Destroying an SDL window seems to deinitialise the opengl state, so the
context needs to be destroyed before the window

steveschnepp/OpenApoc,Istrebitel/OpenApoc,ShadowDancer/OpenApoc,pmprog/OpenApoc,steveschnepp/OpenApoc,FranciscoDA/OpenApoc,FranciscoDA/OpenApoc,FranciscoDA/OpenApoc,Istrebitel/OpenApoc,ShadowDancer/OpenApoc,pmprog/OpenApoc