Bug 937673 - Modify groups model to allow user-created curated groups

* Add flags for functional area, members_can_leave, visible
* Get rid of system, auto_complete, and related fields
Bug 916819 -  Change UserProfile.__getattribute__ to not depend on privacy_fields
Bug 920270 - Basket subscribe API not returning token anymore

The Basket API's subscribe call is going to stop returning the
token and become purely asynchronous. Don't expect the token in
the response, and adapt other code to query Basket for the token
later if we need it.
[fix bug 939752] Update opensearch plugin.

- Update favicon
- Cleanup search syntax
- Use absolutify helper.
Fix bug 942348: Correct GitHub capitalization.
Merge pull request #727 from openjck/github-capitalization

Fix bug 942348: Correct GitHub capitalization.
Merge pull request #723 from glogiotatidis/939752

[fix bug 939752] Update opensearch plugin.
Bug 937729 - Add django compressor extension to Jinja extensions

This will teach Jinja about the 'compress' tag so it can parse
templates that use it when extracting strings for translation.
Merge pull request #728 from dpoirier/bug-937729-string-merge

Bug 937729 - Add django compressor extension to Jinja extensions
Bug 938184 - Don't allow creating groups while editing user profile

Part of the changes for curated groups is that groups will only be
creatable from the groups list page, so only allow people editing
their profiles to select groups that already exist.

The tag-it library that was being used to implement the groups
selection could not easily be configured or modified to prevent
users from selecting non-existent items, so the groups field
was changed to use django-selectable. Styling was added to make
the django-selectable field look like the current tag-it fields,
which are still being used for e.g. skills and languages.
Remove some unused code from groups/forms.py
changing md5 to sha1, opssec says md5 is compromised, sha1 is better
Merge pull request #730 from Sheeri/master

changing md5 to sha1, opssec says md5 is compromised, sha1 is better
[Bug 699530] Add script to anonymize db and copy to stage and dev
Merge branch 'sheerifix'
[Bug 699530] Sanitizer now drops tables that we don't want to copy to dev/stage
Merge pull request #733 from Sancus/drop-tables

[Bug 699530] Sanitizer now drops tables that we don't want to copy to dev/stage
Updating SQL syntax for the DROP statements.
Merge pull request #734 from Sheeri/patch-4

Updating SQL syntax for the DROP statements.
[Fix Bug 938674] Added Create Group button the Groups list page (+2 squashed commits)

only translating the words in the create group button

[Fix Bug 938674] Added Create Group button the Groups list page