Start the session on rest.php, so it avoids impossible to find side effects. Trust me, I lost hours on that one: civi needs a session.
CRM-12446 : support for extension translation (with native gettext only, for now)
Merge pull request #1245 from tttp/crm-13091

Start the session on rest.php
Merge pull request #1255 from mlutfy/4.3-crm12446

CRM-12446 : support for extension translation (with native gettext only, for now)