Do a simple constant blur when determining paint overlay colours.
Do a simple constant blur when determining paint overlay colours.

Fixes flickering issues completely (except where there's no real
background), and looks a bit better overall. Not sure how this performs
on intel graphics, though. Hopefully moving the texture read off the
fragment shader helped at least a bit.

AltSysrq/mantigraphia,AltSysrq/mantigraphia