LL-282 Initial working inplementation.

The circle rename recommendation is working just fine. Using Bootstrap
modal and jQuery UI autocomplete (maybe it would be wise to switch to
typeahead.js, but tha twould require looking into it before making a
decision).
LL-282 #close Refactored the code.

Added CircleRenameModal view, this one will render the corresponding
template. The view is initialized and rendered as part of the AppView
rendering routine. It is stored within it and is later on passed to
WidgetView as an option, this way it is passed to OrganizeView that can
reuse it for the circle lable change.
Merge pull request #3 from learning-layers/feature/LL-282

Feature/LL-282