FIX: Sharing link stood visible after using browser’s back button
Update DEVELOPER-ADVANCED.md

To install the gem pg-0.15.1, you need to have libpq-dev installed. Otherwise bundle install will fail.
See http://stackoverflow.com/questions/16788062/error-running-gem-install-pg-v-0-15-1
API addition: HTTP PATCH support for /groups/xxx: incremental membership changes
Update DEVELOPER-ADVANCED.md

Merged installation instruction for libpq-dev into step 4.
Update DEVELOPER-ADVANCED.md

Fixed numbering of list items.
check that `changes` param is present
Merge branch 'master' into group-admin-incremental
translate welcome message images to cs
Add more SSO logging for failure conditions
Add more logging for blank posts to detect culprit
Merge pull request #2989 from jmay/group-admin-incremental

API addition: HTTP PATCH support for /groups/xxx: incremental membership changes
Merge pull request #2983 from fwoelm/patch-1

Update DEVELOPER-ADVANCED.md
FEATURE: Localize SSO error messages
Merge pull request #2995 from Mikulas/patch-cs-welcome

translate welcome message images to cs
fixing the reply-to tab z-index bug
Merge pull request #2997 from awesomerobot/master

fixing the reply-to tab z-index bug
FEATURE: API endpoint for inviting an admin
test forwarding works as expected
FEATURE: serialize the fact we are https in about
FIX: make IP lookup available to moderators