增加移动版Header和样式表
Minor fixes

* add discourse to sudo
* add `bundle exec` on some calls
* inform user of NUM_WEB/sockets count for nginx config
FIX: Private Message link was broken
Don't show private message button when not logged in
Small visual tweaks to user expansion
Refactor: Topic#invite_by_email

Extract Topic#email_already_existas_for? and Topic#grant_permission_to_user
security issue, anon and logged in users could see the fact that a user sent another user a pm (but could not see the pm itself or title)
No sudo perm for user

Also changed order on informing user that he'll be encountering errors that needs admin access before calling `rvm`.
suggested BBS copy change for inappropriate flag
fix amazon onebox to pull images again
Fix failing spec due to missing variable in extracted method
FIX: Amazon spec
Fixes #1496 - Ember 1.0 regression
User expansion loading improvements
Better unloading of Poster expansion
Changes to user expansion
Make date on User expansion gray
minor copyedit to reduce repetition on dialog
large refactor, ship a few columns from the user table into user_stats
defer view creation on so updates are not performed when people navigate to topics