Fix overriding of config from env vars.
Register a couple ivs configuration variables as envvars.

Since these variables contain sensitive data, we would like to be
able to specify them via the environment.
Fix ivs views.

- Add some missing imports.
- Add requests to requirements file.
- Send verification result to grading API.
uwsgi needs a callable to be able to run Flask apps.

- Added an app callable for server and ivs.
Add sample ansible provisioning config.
Add readme.
No need to supply a Vagrantfile.
Ensure init cleanup updates client collection list.

Made cleanup_collections use get_collection_names and UseResId.
Merge pull request #285 from glowe/gl/fix-config-envar-override

Fix overriding of config from env vars.
Merge pull request #286 from glowe/gl/register-envvars-for-integration

Register a couple ivs configuration variables as envvars.
Merge pull request #287 from glowe/gl/fix-ivs-views-patch

Fix ivs views.
Merge pull request #288 from glowe/gl/uwsgi-conformance

uwsgi needs a callable to be able to run Flask apps.
Merge pull request #289 from glowe/gl/ansible-deployment

Gl/ansible deployment
Merge pull request #291 from glowe/gl/fix-cleanup_collections

Ensure init cleanup updates client collection list.