Merge outstanding pull requests from disqus/gargoyle

[adamchainz]

Currently open PRs and judgment:

1. disqus#3 Condition rename: myapp/gargoyle.py shadows gargoyle package
   ❌ Should be closed, just an absolute_import issue
2. disqus#13 Add session specific controls to dashboard so that users who have permiss
   Possibly useful, but it's a major feature and has no extra +1 requests/subscribers so likely not wanted by many
3. disqus#17 Added Jinja template tag
   Probably useful but likely to need signficant reworking to work with Django's new Jinja template engine.
4. disqus#32 add is_active stringfilter
   Good idea but should rename it or figure out a way of adding a variable to the context.
5. disqus#43 add SwitchActiveMixin to check for gargoyle switch
   LGTM, but no upvotes.
6. disqus#55 Fixed range condition
   ✅ We have merged in #22.
7. disqus#73 Wrap id's of selectors in quotes
   ✅ We have merged in #34 , with nexus jQuery upgrade merged in adamchainz/nexus#43.
8. disqus#92 Add ifnotswitch template tag
   ✅ We have merged in #37.
9. disqus#98 Cannot add conditions in Nexus
   ✅ We fixed the issue rather than merge the documentation update. #34 fixed some of the problems with spaces, #38 fixed the remainder.
10. disqus#103 throw exception when key longer than 64 characters
    ❌ Thought about it in #28, but ultimately consider not worth merging - MySQL users should just activate strict mode

[matclayton]

#55 I wrote originally and the range condition doesn't split up the input data without this patch and will cause a 500, it shouldn't be hard to confirm

[adamchainz]

Thanks @matclayton , will try merge later today!