[fix bug 949080] South migration for twitter usernames.

Remove '@' from the start of twitter usernames.
Merge branch 'gh-788'
[bug 949080] Add missing import in case of error.
[Fix bug 964236] fixed email links and displayed IRC name as “IRC: ____” just as it shows on the full profile
Buttons with the class button-negative in the case of not being negative, no longer get class=“button button”
Change vendor install of unidecode to a PyPI install
Merge pull request #794 from caktus/unidecode

Change vendor install of unidecode to a PyPI install
Merge pull request #781 from caktus/no-button-buttons

no more class=“button button”
[Fix bug 964434] show a membership pending message

Squashed commits:
- cleaned up whitespace
- restored placement of join.leave buttons
- Styled pending status bar just above list of members. Moved “Leave Group” button into the info - box where other buttons appear.
Merge pull request #792 from caktus/964434-membership-pending-message

[Fix Bug 964434] membership pending message
Fix bug 961219 - Filter group members

Curator view of group lets them filter to show only full
members or only pending members
Merge pull request #776 from caktus/961219-member-filtering

Fix bug 961219 Filter group members
Fix bug 962292 - Let curator delete group
Merge pull request #785 from caktus/962292-curator-group-deletion

Fix bug 962292 - Let curator delete group
[Fix Bug 969020] Send pending request emails only once per group
Merge pull request #799 from Sancus/distinctgroupemails

[Fix Bug 969020] Send pending request emails only once per group
[Fix Bug 969044] update django-autocomplete-light to 1.4.13
Merge pull request #800 from Sancus/update-autocomplete-light

[Fix Bug 969044] update django-autocomplete-light to 1.4.13
[Bug 970397] Update ES settings for jenkins
[fix bug 969098] Mark announcement text safe.

- Also added 'u' in allowed tags.