First attempt at minimax. Heuristic based on whether there is a victory state - if not, it counts the number of 3-in-a-rows. Not yet validated and is slow - needs improvement.
Merge branch 'develop'

Conflicts:
	game.js
	game.svg
Changed depth from 4 to 2. Is much more responsive and is still pretty competitive. Interestingly, doesn't make some dumb mistakes that it make at depth 4.