Compositing on CPU sort of kind of works if we ignore Alpha*

*Alpha is hard and I'm just going to ignore it.

Hacky fix to "overflood" problem where the fill point is outside the boundary;
since it can't be more than 1 pixel outside, check the neighbours before starting
the fill.

Unfortunately this means if the fill point is only one pixel *inside* the boundary,
there is no fill.

Tried brute force approach for low resolution paths, but that doesn't really work.
Path::PointInside doesn't seem to succeed where it should...

Other things might have happened.

Not much happened towards actually getting infinite precision,
starting to run out of time, panic mode engaged...

PANIC MODE ENGAGED

PANIC LEVELS AT 100%

EMERGENCY ANTIPROCRASTINATION MEASURES FAILED

PANIC LEVELS AT 200%

ENGAGE SHUT UP AND FIX EVERYTHING MODE

FAILED TO SHUT UP

PANIC LEVELS AT 300%

ENGAGE DINNER TIME

DINNER TIME SUCCESSFUL

PANIC LEVELS STILL AT 300%
apathy levels at 1000%