Space.java
	Added loop for collision detection.
	Added list of objects by collision_type.
Vec2.java
	Added method set that takes and array as argument
Body.java
	Added attribute a
Shape.java
	Changed collisionType from int to Object.
Poly.java
	Moved coded from shape to this file.
	This avoids arguments errors when calling from ruby.
Segment.java
	Move code from shape to this file.