survey summaries are generated via node

a first example of the js / coffee components of the application being
used by django on the server.
moving import_question functionality over to a js util
merged @nstraub's work from question-library branch
jsapp utils for running methods on the xlform survey
minor css changes on library import button (finishes tp #728)
added commander dependency to package.json
Merge pull request #417 from kobotoolbox/tp728

A user can import a question library from XLS file