Updated Enemy AI
If the distance between the player and the enemy is > 15, the enemy will
now patrol in a small square until the distance between the enemy and the
player is < 15

Also added a helpers.py file which we can use for any math calculations
for the future, as of right now it only has a distance function which
could be useful in other parts of the program, but have not implemented
them in the other parts, although it wouldn't be difficult`
Merge branch 'master' of https://github.com/KevinDough/RockGame

Conflicts:
	source/levels.pyc
	source/rocks.pyc