dragEnterClass is only removed, never added.

dragEnterClass is never added to elements, it was probably removed by accident.
Dont remove drag enter class when onDragLeave

Added back the on-drag-enter class code.
Callback for onDropFailure

onDropFailure mirrors the function of onDropSuccess.
Documentation for on-drop-failure
Merge pull request #53 from labdivision/master

Add on-drop-failure (mirroring on-drop-success)
Merge pull request #52 from LordWingZero/patch-1

dragEnterClass is only removed, never added.
workaround for dragend not firing on elements removed from dom
Fixed bug where dropChannel broadcast wrongly on hover.

- When unit testing the code I noticed that when setting
  dropChannel to '*' there would be situations where
  the regex compile in isDragChannelAccepted() would
  fail.  The onDragEnter() handler is broadcasting the
  dropChannel, and the handler for the ANGULAR_HOVER
  event is receiving it and passing it to
  isDragChannelAccepted() as the drag channel.  Changed
  so that onDragEnter() sends the drag channel instead.
fix epic copy paste fail
Merge pull request #57 from mulderr/master

workaround for dragend not firing on elements removed from dom
Merge pull request #60 from jglogan/master

Fixed bug where dropChannel broadcast wrongly on hover.
Preventing native DnD when the drop channel does not match or validate function is false
Merge pull request #64 from dcendents/native-dnd

Preventing native DnD
added  service for simplifying dragImage creation
allow drag-image attribute to accept a string
ability to override default config
Merge pull request #65 from marshall007/master

feat($dragImage): service for simplifying dragImage generation
Removed jQuery dependency for drag handles (fixes #41)

jqLite doesn't allow finding elements by class name, so used another approach
Merge pull request #68 from hansler/master

Removed jQuery dependency for drag handles (fixes #41)
Added Gitter badge