Added static RenderHelper class to help with rendering sprites

The static method renderSprite should be called in the paint() method
of the Engine class.
Fixed Engine class

Made player into a field variable, made currentDirection refer to the
Player class
Fixed Player Class to support Image functionality

Calls the superclass constructor to automatically set it up. Note that
there is no current player image location, so this will not currently
work. Please add Player image location ASAP.