Add RTL support to Discourse CSS pre-processing using the RTLit gem and configurable via discourse.conf
ensure rtlit gem in Gemfile is not required by default
ensure RTLit gem is included and CSS is RTLed if css_rtl is enabled in discourse config
Have reciever handle multiple To addresses
Use same reply-to format in all email fixtures
Add error reply for new error
Implement SSO overriding avatars.

Implemented by having Discourse download the image from the provided URL
and treating it as a custom upload.

Adds two more parameters to the SSO site’s response:

* `avatar_url` specifies the URL of the overriding avatar.
* `avatar_force_update` Discourse does not re-download avatars that
has already been download from the same URL. Setting this to true forces
Discourse to re-download the avatar in `avatar_url`

Note that both parameters are ignored if `sso_overrides_avatar` is set
to false.
Fix min_trust_level for wordpress

min_trust_level in the wordpress method was being set to 1 always, the order of the ternary operator was reversed.
TRIVIAL: fix deprecations due to momentjs upgrade
remove posts column from /categories
FIX: banner on small desktop screen
remove the "view all {number}.." from mobile cat
missed the posts TH on /categories
FIX: vBulletin wasn't importing posters...
FIX: don't use the user's discovery text as bio in vanilla importer
Add link to Logster in "Logs" tab of admin panel
Add Finnish
Update Translations
remove admin link on user drop down
Merge pull request #2681 from techAPJ/update-translations

Update Translations