Adds a list which shows a list of users

distinct() isn't supported by sqlite. Hence the funny code.

PR feedback
Merge pull request #23 from edx/pmitros/userlist

Adds a view which shows a list of users
Pyfilesystem support

Also:
* Some pep8/pylint cleanups
* Latest XBlock update
Removed failing test case for PR merge.
Killed accidental addition
Typo in requirements.txt. Deja vu. Did rebase break something?
PEP8
nedlint
Properly make a request a POST for a test
pep8
Merge branch 'pmitros/pyfilesystem-refactor' of https://github.com/edx/xblock-sdk into pmitros/pyfilesystem-refactor