implement properties remove method
use native array forEach in propertiesEditor.update
fix timeIndicator height when there is a lot of items
fix #39, Removing all keys of a property doesn't delete the property label in the timeline
should not be able to init drag selection on labels, fix #38
update draggable-number.js to 0.4.3
perf: only make timeline dirty if force and not on all time changes, add a third parameter to editor.render
bump version to 1.6.0 and update build files