The initial state for user enabled is now read from config. In addition
a DBus interface is provided exporting this property. This allows
KScreen to determine whether automatic screen rotation is available and
whether the user has it enabled or not.
Furthermore KScreen can change the property and this gets stored into
the configuration. Thus KScreen can offer a user interface to
enable/disable automatic screen rotation as well as enabling/disabling
the manual rotation based on the current user settings.