Charging Momentum

[quantumproducer]

When you hit with a melee attack, your previous 4 inputs are compared to your current direction. For each input with a direction within 2 numpad rotations of your current direction that moved you, gain (Level / 3), rounded up in attack power

Motivation: Fleeing is, in my opinion, too easy. This gives an attacker pursuing a target an attack bonus for catching up to them.

Will need to record previous inputs + if they moved you or not (can be updated by AvatarManager).

See also: #72

[roriholm]

@quantumproducer Another good reason to add a general Momentum component.

[quantumproducer]

@roriholm agree. Added #73