Inbox counts: Add dark unread counts badge, start writing to inbox_count
Inbox counts: fix typo in backfill script
Inbox_counts: corrections on deletes, spams, edits

Conflicts:

	r2/r2/controllers/listingcontroller.py
Inbox counts: fix drift on an empty inbox view
Inbox counts: Do not allow inbox_count to fall below zero
Inbox counts: only unnotify links and comments on remove.

Modmail messages can also apparently use POST_remove, as they're
associated with a subreddit. This wasn't effecting inbox counts, but it
was throwing a 500.

Conflicts:

	r2/r2/controllers/api.py
Inbox counts: Do not verify when db_writes are disallowed
Inbox counts: Stop reading from and remove reliance on msgtime

Conflicts:

	r2/r2/models/link.py
Inbox counts: Make count a link
Inbox counts: Add mark all messages as read

Conflicts:

	r2/r2/lib/js.py
Inbox counts: Show and update unread counts on read/unread