Update notebooks to use the new widget and traitlet paths

IPython.nbformat > jupyter_nbformat

fix typo in cluster profile list

Remove submodules

handle empty but defined SHELL env

Sometimes SHELL can be '',
which should be treated the same as undefined.

from JupyterHub

- fetches node tools locally with npm
- runs bower
- setup.py css uses local less as well,
  so no need to `npm install -g` anything.

require `setup.py css` to run

`bower install` in package repo fetches components

Update keyboard.js (typo)

typo

in case IPython is not present

this will need a lot more work

removing IPython shims

fix bug in stale profile clean up for clusters