StreamBuffer : allow seeking anywhere in live stream
StreamBuffer : allow seeking anywhere in live stream

if start position is not defined (-1), seek to 3 fragments from edge.
howerver, if defined, don't cap position anymore. it might introduce buffer starvation, but it is up to the player to compromise between start offset/live delay and potential buffering.

mangui/flashls,vidible/vdb-flashls,tedconf/flashls,NicolasSiver/flashls,tedconf/flashls,clappr/flashls,clappr/flashls,jlacivita/flashls,NicolasSiver/flashls,hola/flashls,fixedmachine/flashls,hola/flashls,codex-corp/flashls,fixedmachine/flashls,codex-corp/flashls,neilrackett/flashls,mangui/flashls,jlacivita/flashls,vidible/vdb-flashls,neilrackett/flashls