Changes:
* Move FreehandAlgorithm/InkType/RotationAlgorithm/SelectionMode to
app::tools namespace
* Removed ISettings, IToolSettings, IBrushSettings, ISelectionSettings,
and IColorSwatchesStore (and implementations from UISettingsImpl)
* Added app::tools::PreferenceGlue to do some adjustments that
UIToolSettingsImpl was doing
* Remove signals from App related to brush size/angle changes, and current
tool change (there events can be observed directly from Preferences)
* Remove ColorBar::FgColor/BgColor, these options can be observed from
Preferences::colorBar.fg/bgColor
