Switch to Python 3, use python3 entry
Merge pull request #29 from rgbkrk/py3docker

Switch to Python 3 in Dockerfile
[Docker] Make bower installation separate.
install subpackages
use 302 not 301 on /
add a notion of admin users

and an @admin_only decorator for restricted methods
simplify handler setup with default_handlers in modules

like IPython's, but a bit simpler since we don't have
so many services to deal with.
minor fixes to testing utils
add user list handler, first of many
flesh out REST API

can now list/view/add/create/modify users
and start/stop single-user servers