second pass at new friends modal, update specs

- go back to using select2 for "add friend" input (but switch to single rather
  than multiple). fixes style problems with typeahead (completions could get
  covered up by modal-footer when the modal was short enough that the
  completions list extended past it), and more easily allows for matching by
  name as well as email address.
- switch to jquery 2.0 which ui-select2 brings with it
- better ordering of friend list
- remove all references to ninvites, no longer used