More efficient draw calls

SpriteBatch.begin and SpriteBatch.end calls are made once per frame so more draws can be batched. Moved SpriteBatch instance from Model to Game and updated ViewComponent.draw so that it passes down a SpriteBatch instance from Game. More consistent parent/child relationship between Model class and more specific Models for different scenes. Added getCursorX and getCursorY static methods to ControllerHelper. Can now back out of InGameMenuScene.
Added in support for controlling a character in WorldScene and animating the avatar

Renamed various images in sprites/character to make them easier to reference in code. Added directional pad to right quarter of WorldScene screen to control avatar. Added code to perform avatar movement.