Start adding components for Flappy Swift.
Added : Gravity, RotationPhysics and FlappingPhysics.
Add image samples from FlappySwift.
Add Physical, RepeatAnimating and Texturing components.
Update physics to accept more arguments.
Rewrite Structs to use Swift initializers instead.
Components will now pass arguments in callbacks.
Update sample to use new Component API.
Add ObstacleMoving
collisionsWith and contactWith are now optional arguments in Physical.
Remove Flapping when crashing.
Added ObstacleSpawning
Rename to __ComponentInterfacing
Merge pull request #1 from seivan/feature/flappy_swift_component_sample

Feature/flappy swift component sample
Merge pull request #2 from seivan/develop

develop into master.