fix memory leak and infinite loop

Created by: bpnetguy

• EventController s causing more apparent memory leak and infinite loop on low spec devices running single page application
• We're not cleaning our setInterval correctly causing an infinite call every 100 ms https://github.com/Dash-Industry-Forum/dash.js/blob/development/src/streaming/controllers/EventController.js#L95
• Using StreamController controller to clean up eventController on reset
• This causes ~ .2MB memory leak per playback + wasted cpu execution time 1 setInterval per playback switch that never gets cleared.