fix poster mediator event leak (refs #211)
fix poster mediator event leak (refs #211)

dayvson/clappr,kelonye/clappr,Peer5/clappr,Pyrotoxin/clappr,tjenkinson/clappr,MariadeAnton/clappr,burakkp/clappr,kelonye/clappr,leandromoreira/clappr,leandromoreira/clappr,irongomme/clappr,kelonye/clappr,Metrakit/clappr,flavioribeiro/clappr,tarkanlar/clappr,jfairley/clappr,wxmfront/clappr,Peer5/clappr,tarkanlar/clappr,wxmfront/clappr,MariadeAnton/clappr,clappr/clappr,clappr/clappr,shakin/clappr,burakkp/clappr,tarkanlar/clappr,Metrakit/clappr,dayvson/clappr,shakin/clappr,irongomme/clappr,flavioribeiro/clappr,Peer5/clappr,flavioribeiro/clappr,leandromoreira/clappr,burakkp/clappr,wxmfront/clappr,jfairley/clappr,jfairley/clappr,tjenkinson/clappr,MariadeAnton/clappr,Pyrotoxin/clappr,clappr/clappr,dayvson/clappr,tjenkinson/clappr,irongomme/clappr,Metrakit/clappr,shakin/clappr,Pyrotoxin/clappr