Break out progress() to svtplay.output module
Break out progress() to svtplay.output module

Now it is very clear that progressbar() duplicates an existing function. But
obsoleting one or the other is work for the future.

OakNinja/svtplay-dl,leakim/svtplay-dl,dalgr/svtplay-dl,selepo/svtplay-dl,qnorsten/svtplay-dl,olof/svtplay-dl,iwconfig/svtplay-dl,olof/svtplay-dl,OakNinja/svtplay-dl,qnorsten/svtplay-dl,dalgr/svtplay-dl,selepo/svtplay-dl,leakim/svtplay-dl,spaam/svtplay-dl,iwconfig/svtplay-dl,leakim/svtplay-dl,OakNinja/svtplay-dl,spaam/svtplay-dl