fix getToggleElement on dropdown by updating to angular-bootstrap 0.12.0 #250

details on breaking changes:
https://github.com/angular-ui/bootstrap/blob/eec68d81f4f72363d37493c495b
892347bdb9e1b/CHANGELOG.md
@jeromegv you forgot to remove this line. @amoshaviv @lirantal can one of you just delete the 0.11.2 dependency?