Added toString() and serialize() to Vec2. Resolves #5
Added information for contributers.
Deleted the engine2d library.
Fixed a bug with the collision.
Refactored CollisionResult.
Changed package author
Added average, degToRad and radToDeg functions
Added center property to Shape classes.
Renamed vector.dart to vec2.dart
Changed public members of Vec2 to use num instead of double.
Added documentation for toString() and serialize().
Added unitX and unitY constructors to Vec2.
Improved Vec2 documentation.
Added Vec3 class
Added Vec4 class.
Fixed minAll and maxAll not returning.
Added documentation to all existing members.