Add animation to mdl-dialogs

[mseemann]

No description provided.

[andreialecu]

I haven't tested yet, but it would be nice if you could pass an $event to the modal open function so that the animation appears to pop-up from the button/link it is triggered by.

This would be pretty nice for a certain app I'm working on, as there are a lot of clickable items and the visual feedback would be nice.

[mseemann]

please open an issue that coves this problem. i think there is a lot to talk about. for example: how to pass custom animations to the dialog. right now the animation is done with the angular2 dsl for animations and i have no idea how i could allow others to pass their own animation... thx!