- The pyglet backend should provide its own equivalent for wx.SimpleApp,
  i.e. opens a frame and runs the main loop.  The pyglet backend's Window
  should work like any other backend's Window class, and expect a main loop
  to be running.

- Small error in Pyglet Programming guide windowing.txt:
        window.Window(fullscreen=True, screens[1])
  should be:
        window.Window(fullscreen=True, screen=screens[1])

- Another error in Pyglet Programming guide mouse.txt: the mouse capture
  method should be named set_exclusive_mouse(), instead of
  set_mouse_exclusive()

- Integration with WX/qt?  (e.g. TraitsPygletWindow)

- Use pyglet.clock to implement EnableTimer on it

- Need to figure out how to handle double clicks since we don't natively
  get those from Pyglet

- Extend Enable to support horizontal scrolling

- We should support on_text_motion and on_text_motion_select, but only text
  widgets and components would care.  Right now Enable doesn't have any
  concept of distinguishing different kinds of components.  It would be a
  good thing to add.