Implement Momentum about iona HOT 2 OPEN

I think we need an acceleration vector that alters velocity, instead of setting velocity to a constant amount.

from iona.

I've implemented the acceleration vectors. Now we need to implement some homing functionality for the enemies. They need to detect how much time it's going to take to get the player based on if the player is moving away from or towards them (or sitting still) and then aim for the spot where the player will be, instead of where they are.

from iona.