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
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.
Merge pull request #2670 from Wilhansen/sso_override_avatar

Implement SSO overriding avatars.
Merge pull request #2633 from zohararad/master

Add RTL support to Discourse CSS Theme
Merge pull request #2675 from amalagaura/patch-1

Fix min_trust_level for wordpress