Add support for specifying codec in carrier_gateway table

Add ability to test ${} queries even when no session is
 available (abuse events for this)
Test sql at startup, refuse to load invalid profile


git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@12688 d0543943-73ff-0310-b7d9-9358b9ac24b2