PlayerControls: only enable rewind if there is a valid logfile
PlayerControls: only enable rewind if there is a valid logfile

magmaOffenburg/RoboViz,magmaOffenburg/RoboViz,pmacalpine/RoboViz,pmacalpine/RoboViz,pmacalpine/RoboViz,magmaOffenburg/RoboViz,magmaOffenburg/RoboViz