Add generic shape matching methods + example to test overlap tests

[mflerackers]

Shapes now have the following methods

collides(shape: any): boolean - Test overlap with any other shape contains(point: Vec2): boolean - Test if a point is contained by the shape

[slmjkdbtl]

Thank you this is useful! Can you fix the diff noise in math.ts it's making it hard to view actual diff

[slmjkdbtl]

Thank you!