Issue Title: Moving diagonally sometimes costs 1, sometimes 2 AP
Issue Description: As described in title. Movement costs for diagonal movement seem inconsistent.
Screenshots 1 and 2: Moving diagonally and orthogonally cost same amount of AP
Screenshots 3 and 4: Moving diagonally costs 1 AP more than orthogonally
May not be a bug, may be working as intended, but if so I think you need to include some information on how movement costs are calculated, because I cannot for the life of me figure out what rule it follows.
Steps to Reproduce: Happens all the time when moving agents.