* unsettings/converter.py:
  - added logging to DictConverter.convert, .rev_convert
* unsettings/main.py, unsettings/backends.py:
   - added 'gi.require_version()' statements
* unsettings/ui.py, data/ui/unsettings.ui
   - added gsettings://com.canonical.Unity.Launcher launcher-position
   - added gsettings://org.compiz.unityshell:/org/compiz/profiles/unity/plugins/unityshell/ launcher-capture-mouse
   - added gsettings://com.canonical.notify-osd gravity
   - added gsettings://com.canonical.notify-osd multihead-mode
   - added gsettings://org.gnome.desktop.wm.preferences action-double-click-titlebar
   - added gsettings://org.gnome.desktop.wm.preferences action-middle-click-titlebar
   - added gsettings://org.gnome.desktop.wm.preferences action-right-click-titlebar