ball can now store player id (global)

This id represents the player that last hit the ball
Moved lastHitBy from ball to circularbody
ID of player is now saved on collision
Score is incremented on the server when a pole is hit

For now it is also possible to hit yourself and get extra points. This
will be fixed in a next commit.
Players can now hit each other and get points for it

The points are also taken from the settings for easy editing. For now
the players can still hit themselves or hit a player multiple times
when it is trapped between their pole and shield. This will be fixed in
an upcoming commit.
HitBy is reset when a player is hit

So the player can only hit one other player per ball he bounces off
with his shield.
Added documentation to new functions that weren't documented yet.
Points player is worth now depends on place in highscore
Merge branch 'ballLastHit' into development

Conflicts:
	src/server/ServerGame.js