Accepting multiple need ids from the view

also masking the input to be a six-digit numeric
field to make sure the input looks like a need id.
Correcting test name to reflect what it does
Added a test around GET /artefact json api
Show multiple needs on Artefacts Index page
Removing need description from artefact edit view

also, making changes to the tagged inputs to
make need id tags more prominent and
appear as a list.

removed unused `need_id_numeric?` method.
Maslow need id tags are links to the need in maslow
Updating tests to use multiple need_ids
Update cucumber features to test multiple need ids

also, marking tests that need javascript
and making them use poltergeist driver.
Bump content models to support multiple needs