MediaController: Update position while queuedPositionUpdate timer is running

Authored by drosca on Jan 1 2017, 3:35 PM.

Description

MediaController: Update position while queuedPositionUpdate timer is running

Also don't try to call SetPosition when position didn't change.
Fixes sometimes reseting position to 0 after expanding applet.

Differential Revision: https://phabricator.kde.org/D3904