add: a better singleton class.

Signed-off-by: liuyanghejerry <liuyanghejerry@126.com>
update: use Singleton for BrushManager.

Signed-off-by: liuyanghejerry <liuyanghejerry@126.com>
update: translation.
update Japanese translation.
upadate translatons.
lupdate & lrelease translations.
add: basic shortcut manager.

Signed-off-by: liuyanghejerry <liuyanghejerry@126.com>
Merge branch 'singleton' of gitcafe.com:liuyanghejerry/painttyWidget into singleton
update: use shortcutmanager.

Signed-off-by: liuyanghejerry <liuyanghejerry@126.com>
Merge branch 'singleton' into dev