Prevent click's event (on a calendar) to propagate

In this situation, on Ionic framework:
![image](https://cloud.githubusercontent.com/assets/1862580/2765548/b185213c-ca25-11e3-9ab0-b19c8c94775c.png)
when I click on f.e. day no 12, the calendar changes the day (ok), hides the popup (ok), but the event propagates to upper scope and in the same time "Post it!" button is clicked in submitted (not ok).

This is because "selectDay()" happens onmousedown, not onclick, so when I finish click, the popup is already closed.

This fixes it but shouldn't remove any previous behaviour.

P.S. Why is there `ng-mousedown` instead of `ng-click` anyway? ;p