Preference/UI Refactoring

- Added res/icons/test_sound.png

- AltMenuScreen uses UserInterface for game icon

- ButtonPanel, removed extra stuff and PreferencesModel declaration

- MainPanel, switched to use JLabels instead of convoluted pain(t)
method

- PreferencesController is still in process; TODO: Add handling for
events from PreferencesViewer

- PreferencesModel, simplified Screen Size check and removed
setScreenSize return value, added defaults set from UserInterface, fixed
error in checkArgument for Music Volume

- PreferencesViewer, refactored to make it more readable and hopefully
better design

- Added UserInterface class to hold various user interface things

- Added UITestApplication because I had been previously changing Sprint1
and other which was bad of me because then my edits will wind up in
Production and potentially screw others