TODO for the gtk renderers:

* get selected="true/false" to work properly in clists and trees, should be able
  to set the currently selected item from entity.
* Fix graph renderer
* Fix radio buttons

<<done>>
* tooltips
* progress text
* checkbox  (DONE)
* radio     (DONE)
* notebook  (DONE except for _delete)
* tree      (need dnd and _delete)
* scrollwin (DONE)
* list      (DONE)
* paned     (DONE)
* convert all the true/false checks to use rend_is_true (). (DONE)
* add the ablity to have label="" attribs in tags that lables are common.(DONE)
* dropdown (gtkcombo (combo is a dumb name)) (DONE)
* Text renderer's scrolled window needs to be embedded (DONE)
* add idler ablity to timeout
* notebook label="" seems broken.
* doubleclick support
* fix keyrelease
