Remove pre-existent markers on reinit
Remove pre-existent markers on reinit

This allows you to change the markers over time (by feeding new arrays and forcing re-initialization)
ereztison/videojs-markers,phelma/videojs-markers,spchuang/videojs-markers,Sly777/videojs-markers,bianjp/videojs-markers,mkravchuk7/videojs-markers,phelma/videojs-markers,ereztison/videojs-markers,mkravchuk7/videojs-markers,Sly777/videojs-markers,bianjp/videojs-markers