Allows some media service backend to provide the ability to can play media in the background while the application is terminated. Change-Id: Ia5e751367f6d6ea6847c3c873b45df5f971557e2 Reviewed-on: http://codereview.qt.nokia.com/3561 Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com> Reviewed-by: Michael Goddard <michael.goddard@nokia.com>