Vocab widget: minor changes:
  - added a debug mode - chuck a '&debug' onto the querystring
  - introduction of an 'allnarrow' mode: this performs an allNarrower.json
    call, instead of the normal 'narrow.json' call
  - expose narrower terms (thanks to Ben for providing this information
    without my having to retrieve children to determine it myself)
  - removing useless gif loader

Vocab widget: updates to 'tree mode' ui helper:
  - you can now click on a branch icon (open/close) to open and close, not
    just the branch text
  - leaf nodes are now marked up accordingly
  - making a selection fires a "treeselect.vocab.ands" JS event, whose
    callback is passed the original "click" JS event object (which includes
    the target list-item, which has the vocab data under
    $(elem).data('vocab')
Vocab widget: squashed a bug where i'd end up working with a srtring item instead of an array. bit odd, not sure how it's happening.
Vocab Widget:
  - widgetised 'tree mode' - just call
    $(<selector>).vocab_widget({mode:'tree',repository:[repname]) to
    invoke, and listen out for 'treeselect.vocab.ands' events (which
    get passed the original 'click' event the triggered the selection).
    the event target has a 'vocab' data object with all the goodies inside