Simplify (and make more generic) start_stop event functions
Simplify (and make more generic) start_stop event functions

Issue: #109
Change-Id: Ie0dd850ddbb95987cc45b196d8cc129d2efd7478

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