Added missing implements clause for EventSource.
Added missing implements clause for EventSource.

Dador/libjass,joshuabrown-ellation/libjass,joshuabrown-ellation/libjass,joshuabrown-ellation/libjass,Arnavion/libjass,Dador/libjass,Arnavion/libjass,Arnavion/libjass,Dador/libjass