Merge pull request #23 from ninio/master

This fixes the issue #22
Added a destroy method which removes the bindings created, this to avoid memory issues
Merge pull request #26 from NAndreasson/destroy

Added a destroy method which removes the bindings created, this to avoid...
Merge pull request #27 from ninio/master

Fix calling onItem for all the instances of contextmenu that use the same dropdown.
Merge branch 'master' of https://github.com/sydcanem/bootstrap-contextmenu