Merge pull request #2856 from awesomerobot/master

changes: topic title editor layout, badge alignment in scrolled header
Added easy impersonate route while in development mode
Also import Q+A comments
security updates, firewall note
UX: Remove sortable column from "Topic" and "Users" column.
FIX: Clicking "Latest" while ordering by a column should reset the
order.
FEATURE: trust level 3: likes received must be on min_likes_received/3 different days, and be from min_likes_received/4 different users
Merge branch 'master' of github.com:discourse/discourse
More deprecations to allow us to work on future versions of Ember
FIX: Editing a topic's title should be rate limited too.
FEATURE: import attachments in phpbb3 importer
FIX: Autoplaying videos, updates onebox gem.
remove debug puts
FIX: badge granted titles were not being revoked when badge was revoked
FIX: handle paste events for auto completed fields
FIX: add missing transliteration rules
FIX: not showing any search results when scoped on user
FIX: after visiting "top" unread/new tip rendered in large font
FIX: streaming incorrect events into all tab
Added transliteration for extra diacritics