svn merge -r 82869:83166 svn+ssh://svn.lindenlab.com/svn/linden/branches/Branch_1-19-2-Server --> release

Includes:
DEV-12492 "new" regAPI fails on php-framework-2
DEV-11540 Show browser HUD for A/B test users coming from SL.com.
DEV-11730 LLSD parser changes
PHP logs to syslog
DEV-12146 php llsd_UUID does not pass the IsUUID() validation function
DEV-12356 oldstyle FetchInventoryDescendents should be TEMPLATE not LLSD
steve's fix to setting the proxy option in curl