Change welcome element collapse animation method to "slideUp".

* This somehow fixes the problem with the unsmooth animation.
Add user dropdown to navbar and day position text.

* Add "welcome" property to $rootScope as flag for when to display
  "welcome" element.

* Fix bug where "$auth" not user data from server correctly.

* Add bootstrap/dropdown js.

* Update navbar styles and dropdown with user name.

* Add text displaying position of "$tasks.date" relative to today.