Various cleanups to Ubuntu installation instructions:

* Avoid editing /etc/apt/sources.list add nginx repo, instead create
  /etc/apt/sources.list.d/nginx.list

* Avoid editing /etc/nginx/nginx.conf, instead put server_name_hash_buckets
  setting into discourse.conf

* Proper-case Discourse when it is referring to the product name, so that all
  the lowercase references are to the user created during the installation
Address @Supermathie's concerns in PR1430
internationalize Discourse.Formatter.tinyDateYear
Allow groups to be used as aliases for user mention

when configured by the admin a group can be found through the @mentions
feature in both the compose/reply and the private message user-selectors
and once selected the mention will be replaced by the list of users in
the group
move alias levels into enums
internationalize Discourse.Formatter.tinyDateYear
   missed client.??_??.yml
Fixing padding for misaligned small logo URL
A failed attempt to upgrade ruby in the vagrant image using chef. Everything works except setting the default ruby. The command is successful, but doesn't change the default ruby. Stumped.
Default should be to poll every 5 mins
Updated French translation
minor copyedit on deleting user
increase delete user max age from 14->60
Update favcount.js to v1.4.0
only update title if it changes
incorrect warning on site setting
use_ssl is just confusing, it means use_https , fix name of setting
BUGFIX: attempt to forward on the protocol set by haproxy
BUGFIX: mobile ui was being cached for anon views
BUGFIX: fix broken spec
bench improvements