- Added basic physics
Merge remote-tracking branch 'origin/master'

Conflicts:
	core/src/main/java/platformer/core/model/GameState.java
	core/src/main/java/platformer/core/model/gameobject/impl/LevelTile.java
	core/src/main/java/platformer/core/model/gamestate/impl/GameStateImpl.java
	core/src/main/java/platformer/core/model/viewportrender/impl/DefaultViewportRender.java