mdFabSpeedDial: add support for data- and x-prefixes when using ng-repeat

[Frank3K]

On the current master (e6c757c) the md-fab-speed-dial is missing support for the data- and x- prefixes for ng-repeat. The directive does work, however the animations are incorrect: the animation for a 'down'-speed-dial goes both down and up (i.e. it is shown above the fab-trigger).

Demo (regular demo with data- added): http://codepen.io/anon/pen/xGWabe

I think the issue comes from the following part of the code:

        if (children.attr('ng-repeat')) {
          children.addClass('md-fab-action-item');
        } else {
          // After setting up the listeners, wrap every child in a new div and add a class that we can
          // scale/fling independently
          children.wrap('<div class="md-fab-action-item">');
        }

[topherfangio]

Indeed, thanks for catching this.

[topherfangio]

Still working on this, should have code merged this week.