Implemented dragging items
Changed request-reflow and request-repaint into events
Extended Range with an Emitter mixin
Consistently using Emitter instead of home-baked event emitter everywhere
Replaced mouse events with touch events for CustomTime
Documented current time bar events
Replaced hom cooked event emitter with emitter-component module
Removed redundant events.js
Implemented options `selectable` and `editable`
Replaced Item.getWidth with a normal property, and ItemRangeOverflow makes a special property with getter/setter
Fixed selected ItemRangeOverflow not displaying as selected
Timeline items can now be deleted
Dragging left and right side of a range almost working
Merge remote-tracking branch 'origin/develop' into develop