use top-left heuristic for vectorio.Polygon

[kvc0]

this flips the bottom-right style to top-left which is at least
kind of normal. A 2x2 square at (0,0) would be defined like
(0,0), (3,0), (3,3), (0,3)
Which seems kind of surprising but at least less bonkers than
that square being defined at (1,1), which is the current behavior.

[
  (0,0),
  (5,0),
  (5,10),
  (0,10)
]

points as above create the interior pixels below

[jepler]

👍 We discussed this on Discord. Assuming I understand what I'm seeing in the attached image, it's the result I was looking for. This is the usual definition used in 90s pixel graphics pipelines like OpenGL, so while no choice is 100% intuitive to a new user, this rule is backed up by practice.