Refactor Input Event Handler to handle multiple layers

[Christofosho]

Input.js currently only executes functions from one map of inputEventHandler functions. Specifically, right now map functions are the values to the input keys. If we want to execute a function from the player module, using the inputEventHandler object, we would end up overwriting the current function.

We need to look into asynchronous concurrent execution to assure the player movement is drawn at the same time as the map movement, as well as object and npc movement.

[galoompa]

I don't think we should do this... we only want one function to handle the input events.

[aj-r]

I agree with Peter. For the player layer, we've created a new MAP_UPDATE event that you can use to determine where the map is moving, so you shouldn't need the inputEventHandlers