playerendpoint: Reset timestamps when player goes to stop
playerendpoint: Reset timestamps when player goes to stop

Change-Id: I96eb766893b5033d42b4d6b9e687032b8653907d

ESTOS/kms-core,TribeMedia/kms-core,shelsonjava/kms-core,shelsonjava/kms-core,ESTOS/kms-core,KurentoLegacy/gst-kurento-plugins,KurentoLegacy/gst-kurento-plugins,ESTOS/kms-core,TribeMedia/kms-core,shelsonjava/kms-core,KurentoLegacy/gst-kurento-plugins,shelsonjava/kms-core,KurentoLegacy/gst-kurento-plugins,TribeMedia/kms-core,Kurento/kms-core,Kurento/kms-core,ESTOS/kms-core,Kurento/kms-core,TribeMedia/kms-core,Kurento/kms-core