- Move all Swing classes to GUI.Swing and rename them.

- Added ability to create JPanels with the <composite> tag, which can
still by styled normally.
- <composites> can have inifnite composites (and other widgets) in them
but will slow down eventually.
- Styles are now applied after creating the widget heirearchy, but
before the window displays.  This allows for more parent-child relations
and makes them more predictable.