Angular-complied clone for drag. Graceful handling of different task heights.

* Make task drag helper an angular-compiled clone of the original (with the same
  directive scope) in the case where the task is coming from the backlog.  This
  clone is removed from the DOM when dragging stops.

* Add a task-directive-scoped property called "drag" that indicates whether or
  not the task element is currently being dragged.

* Add logic to modify the style of the task element depending on the duration
  (height) of the task so that the font size fits inside the task element.

* Add logic to change what style class is the task has depending on the it's
  duration so that the contained elements stack properly for small sizes.

* Modify stylings of info in tasks.