Removing dropped tab support - this feature was removed in bootstrap 3 (see https://github.com/twbs/bootstrap/pull/6342).
Adding tests for the constructor.
Adding a test to ensure that the layout function will activate the drop down tab when it contains an active tab. Also adding comments to the layout function.
Ensuring tab drop is only called if the element it is called upon is a bootstrap tab or pill container (i.e. has the nav-tabs or nav-pills class).