Fixes for Vector and Ship.

changelog:
	SHIP
	- Collision comments finalized
	- Collision code finalized
	- Velocity code finalized
	
	VECTOR
	- getDirection code improved
		Will now work correctly for any real double value.
		Will return NaN for double inf and NaN Vectors.
		Will return the correct direction for single inf Vectors.
	- getLength code improved
		Will now work correctly for all Vectors
	- normalize code improved
		now based on getDirection() instead of on getLength().
		This makes it work correctly for all Vectors.
	- Vector documentation finalized.