mask collision

it's happeniiiiiing!

in the end after messing around with really complicated things and hours
of debugging, doing it almost exactly the same as rectangle checking was
the solution! It's much more precise than rectangle checking though!

small bug on testing: moving into a thing on the right caused the
character to hover a few blocks up sometimes. maybe due to the character
model? i'm sure there's a fix but right now i must victory shower!