[fix bug 1026962] Display a comment with a user's vote on a budget poll.
[bug 1026956] Extend polls with no majority decision for 24 hours.

* Send reminder email marked as urgent on voting extension.
* Migrate remaining voting cronjobs to celery.
* Remove unused daily voting reminder cron.
Merge pull request #786 from akatsoulas/1026962

[fix bug 1026962] Display a comment with a user's vote on a budget poll.
Merge pull request #798 from johngian/1026956

[bug 1026956] Extend polls with no majority decision for 24 hours.