Updated TODO list and added quit key
Merge branch 'master' of https://github.com/atomictom/WiseGuy
Made some cosmetic and architectural changes

Changed comments, doc strings, and a few architectural things
(e.g. Simulation is now a GameObject).
Added mouse event handlers

There are several raw and "generated" mouse event handlers that can be
hooked now. The "raw" ones are called on mouse input events and are
mouse_move, mouse_up, and mouse_down (up/down = pressed/unpressed). The
generated ones are mouse_click, mouse_enter, and mouse_exit (generated
from the other events as a convenience).

All of these can be overriden, but if so the super method should be
called to propogate the event and set proper variables (which the
generated events rely on).
Added an infobox area and a button base class

The infobox is to eventually be filled with information about the
player, environment, and buttons to edit the environment.

The button class is a base class which can override the new mouse event
handlers to provide editing functionality to the simulation and should
be placed in the infobox.