Fix video playback
Fix video playback

The picture-in-picture is now disabled in video playback mode, replaced
with a crude 'Back' button. We may be able to restore the ximagesink hack
in a future commit (using a separate pipeline, since it doesn't mix well
with the current one)

godiard/record-activity,ceibal-tatu/record-gnome,linux4kix/Record.activity