Added clearMF method which clears the currently set (whether it be dynamically or automatically set from url) media fragment, even when currently playing or displaying it. Added playmfonce method that plays the fragment (either dynamically set with st,et,x,y,w,h arguments, or previously set with no arguments) and then clears the fragment when finished or the user has seeked outside of fragment. Use playmfonce when you want to replay a fragment once and only once i.e. going back later, the fragment will no longer be there.