Save last action dialog state
Remove access to items through shared pointers
Fix displaying images in tray menu
Clean up slots
No saving in load functions

QSettings objects shouldn't be changed in load* functions.

When saving to application settings the safe Settings object must be
used so the settings is not lost. The reason is that QSettings flush
operation is not atomic -- it clears configuration, without back up, and
starts saving new values.
Get rid of Qt warning

Command dialog seems to be deleted too soon triggering following
warning.

  QCoreApplication::postEvent: Unexpected null receiver
Updated translations