Very minor changes in semantics due to previous differences:
* negative positions are not supported any more (clamped to >= 0)
* setting muted to the same value previously set to the control itself
won't signal any more.
Change-Id: Iacf4310508d853ae82b63dee28095fce12b6ff28
Reviewed-by: Dmytro Poplavskiy <dmytro.poplavskiy@nokia.com>