adding draggable feature to this project

[landonsilla]

I added the ability to drag/drop and reorder labels. Just add dragtag=true to the . Additionally, there is a onTagDragged option to call a function after a "drop" has occurred. This was asked for in this issue:
#168

Enjoy!

[coveralls]

Coverage decreased (-8.8%) to 90.975% when pulling f8e78bb on landonsilla:master into 87d0e6b on mbenford:master.

[roywkc]

seems like onTagDragged was not chained onto events.
Added this and it worked
events.on('tag-dragged', scope.onTagDragged).on('tag-added', scope.onTagAdded)