UI: Moving html files to a src/ui folder.
Getting rid of line to force non-power-of-two texture support.

This was added for cefpython, but things seem to run fine without it. If
it is still needed, it should be added to the CEFPanda class instead of
main.
Renaming cefexample.py to cefpanda.py
UI: Moving CSS to an external stylesheet.
UI: Cleaning up the indentation on the combat UI code.
Renaming ui.html to combat_ui.html.
Cleanup: Removing a debug key binding from the CombatState.