Merge pull request #42 from andystanton/aabb-collision-detection

Aabb collision detection
Merge pull request #47 from andystanton/aabb-collision-detection

#46 add initial overloaded operators to Vec2
#44 remove unique_ptr from vec2 functions
Merge pull request #48 from andystanton/remove-vec2-unique_ptr

#44 remove unique_ptr from vec2 functions
remove needless unique_ptr