VideoViewer: Add frame slider.
VideoViewer: Add frame slider.

tschmidt23/Pangolin,renzodenardi/Pangolin,randi120/Pangolin,stevenlovegrove/Pangolin,wxdzju/Pangolin,mp3guy/Pangolin,tschmidt23/Pangolin,wxdzju/Pangolin,stevenlovegrove/Pangolin,mp3guy/Pangolin,arpg/Pangolin,renzodenardi/Pangolin,randi120/Pangolin,tschmidt23/Pangolin,mp3guy/Pangolin,arpg/Pangolin,stevenlovegrove/Pangolin