Update django-taggit from 0.9.3 -> 0.11.2

For Django 1.6 compatibility.

Update django-sitetree from 0.9.4 -> 1.0.0

For Django 1.6 compatibility.

Update django-reversion from 1.7 -> 1.8

For Django 1.6 compatibility.

Upgrade django-markitup from 1.0.0 -> 2.1

For Django 1.6 compatibility.

Remove outdated fixture_gen files

http://github.com/alex/fixture_generator has not been updated since
Django 1.2.

mimetype -> content_type

mimetype is deprecated and to be removed in Django 1.7.

Use {% load url from future %} in dashboard template

Using https://github.com/futurecolors/django-future-url

Use {% load url from future %} in team templates

Using https://github.com/futurecolors/django-future-url

Use {% load url from future %} in sponsorship templates

Using https://github.com/futurecolors/django-future-url

Use {% load url from future %} in speakers templates

Using https://github.com/futurecolors/django-future-url

Use {% load url from future %} in schedule templates

Using https://github.com/futurecolors/django-future-url

Use {% load url from future %} in reviews templates

Using https://github.com/futurecolors/django-future-url

Use {% load url from future %} in proposals templates

Using https://github.com/futurecolors/django-future-url

Use {% load url from future %} in emails templates

Using https://github.com/futurecolors/django-future-url

Use {% load url from future %} in conference templates

Using https://github.com/futurecolors/django-future-url

Use {% load url from future %} in cms templates

Using https://github.com/django-future-url

Adds a manage.py script to assign reviewers to talks.

Requires that a 'reviewers' group exist, and that there are people assigned to it (otherwise it won't find any reviewers to add!).

It will assign up to 3 reviewers, where those reviewers are NOT one of the speakers, and that reviewer has not opted out of reviewing that talk. It will choose random reviewers from those with the fewest existing not-opted-out assignments.

remove starter project bits from the module repo

see https://github.com/pinax/pinax-project-symposion

Provides a better error message when a sponsor benefit text field is longer than the allowed limit.

It tells you how many words you've written!

Update symposion/templates/sponsorship/_sponsor_link.html

Improved reference format and used pk rather than id
- thanks to trbs for the suggestion