* In GuiBackground, we now load and use all of backdrop.jpg. This is for effects like that in Jade. It's an extremely minor change, so shouldn't effect stability.
* The alternate theme is just useful for testing themes, but please comment on the changes to the main theme.
* Options reading and initializing separated from UI.
* Options UI abstracted a bit, made more easily extensible.
* With some extension, the options UI could be used as the basis for more complicated themes, if we load a file and use it to do stuff like GameStateOptions::Start()