Sync catalog hidden threads from catalog page.

Fixes HTTP/HTTPS issues, but introduces race condition issues.
Merge branch 'cataloghiding2'

Conflicts:
	src/Filtering/ThreadHiding.coffee
Move to push-push design for hidden threads sync with catalog.

Only changes to the list are pushed.
Fails at syncing with catalog across http/https, but fixes
the issue where changes to the list would be reverted.