fixed broken vao redundancy removal in compileDiff (old vao was created with current surface which is invalid if old.surface<>new.surface)
fixed broken vao redundancy removal in compileDiff (old vao was created with current surface which is invalid if old.surface<>new.surface)

vrvis/aardvark.rendering,vrvis/aardvark.rendering,vrvis/aardvark.rendering,vrvis/aardvark.rendering