Added the fife_settings.py extension. This provides a small utility class for loading and saving settings along with a dialog box for setting screen resolution and other things. Updated the shooter demo and rio_de_hola to use the new settings extension.

<?fife type="object"?>
<object id="cannonspread5" namespace="http://www.fifengine.de/xml/tutorial" blocking="0" static="1">
	<image source="cannon_spread.png" direction="0" />
</object>