Add new private message button on topics list

That'll teach me to wildly refactor things.
Add test for email with inline reply
Merge pull request #3016 from techAPJ/patch-4

FIX: if full user name is not provided, username should be present in em...
FIX: change top score formula

Adds more weight to `likes` (it's now the same weight as `post_count`)
Merge pull request #3009 from gdpelican/feature/new-private-message

New Private Message button for user topics
SECURITY: prevent direct download of backups
refactor fix in 67c4c90159428d700766ac610ca374d764cea6a7
FIX: private message button wasn't adding the recipient (cc @gdpelican)
Merge pull request #3012 from techAPJ/patch-2

Add test for email with inline reply
FIX: reload current page when deleting a user
Introduce support for other tuneable GC vars
Upgrade to 1.8.1: So long, metamorphs!
Tweak suspect list to make sure any accounts listed are older than 1
day.
FIX: Don't show `undefined` in the footer text.
remove unused site settings company_domain, company_full_name, company_name
FIX: If we are scheduled after being torn down don't do anything
FIX: Word null appearing in user card
FIX: Check if the bio_cooked exists before outputting it.
Patch Ember to fix https://github.com/emberjs/ember.js/issues/9805
FIX: Broken comboboxes. Workaround Ember bug that needs triaging