* Change filtering from single selection to logically and each filter type.
* Remove clear filtering button and logic.
* Filter buttons now behave as true toggle buttons.
* Improve list control pane focus following when using arrow keys to change
  list pane.
* Remove unused parameters from list box constructors.
* Make tab key behave like right arrow key when moving focus to next list
  pane.
* Make list pane focus wrap around to next or previous control.
* Simplify component list filtering code.
* Improve status bar updating.
* Tell Bazaar to ignore .downloads-by-cmake instead of downloads-by-cmake.