Improvement #41: Enable/disable redirection through D-Bus

- Add "redirected_force" to D-Bus opts_get to forcefully
  redirect/unredirect windows.

- Add D-Bus method "repaint", to, namely, repaint the screen.
Misc: stoppaint_force & Documentation update

- Add stoppaint_force option, controlled via D-Bus, to stop painting
  completely, which may look better than unredirecting the screen,
  sometimes. (#41)

- Add x2, y2 matching targets.

- Update documentation.