Show 'synonymous' instead of all non canonical tags

Noncanonical tags encompass both unfilterable and synonyms.

There was already a column to show unfilterable tags only.

The 'noncanonical' column was showing unfilterables and tags that had been merged with synonyms (mergers).

Now there is a 'synonymous' column instead, which shows only non-canonical tags that have synonyms.
When sorting by taggings count, also provide secondary sorting by name

Taggings count don't provide enough order - when too many tags have the same number of uses, the results of sorting are unpredictable and the order keeps changing.

This adds secondary sorting by name, ascending, when the taggings count is the same.
3652 unclosed HTML tag on user signup page
3620 mention podfic in inspired by field on new work form
3761 Caution for draft page warning
Merge branch 'refs/heads/master' into issue-1891-view-synonyms-only
Merge branch 'refs/heads/master' into issue-3278-sorting-taggings-count
Adding specs to the tests run on Travis-CI
Add rspec tests
Adding RSpec to Travis-CI
Adding RSpec tests to our Travis-CI setup
Adding RSpec tests to our Travis-CI setup
Adding RSpec tests to our Travis-CI setup
Run RSpec tests on Travis-CI
Shorten up the Travis.yml file
More changes
Trying something new
Split them up travis
bundle it
Spell things correctly