Add ng-click and button type to scope filtering

* This addition gives the user an ability to specify a submit function
  so that it can be used as a normal button that does an action — may be
  update some attribute by fetching data from the server — and not just
  a form submit. This will make it act more like a normal HTML button.

* The button type can be set which gets parsed as a string.
The main idea of this change is that the button can act as any plain button by setting the `type` attribute to `button` instead of the default which is `submit`.

The default idea is that the plugin will be used to submit a form and that, the submit function will be passed as a value to the `ng-submit` parameter of the `form`. But this might not be the case when I would want to fetch some data from an API to, say, update some other attribute.  A plunker to demonstrate the idea: http://plnkr.co/edit/wnkwTR?p=preview

( the `ng-bs-animated-button.js` code in the plunker has been modified to suit the changes here )