[SR-Users] sample SCA kamailio.cfg added

I've added a basic working kamailio.cfg with Shared Call Appearances to the SCA docs. It should help clarify where and when it's necessary to have the sca module inspect traffic. Those of you simply wanting to test SCA can just copy and paste the configuration, updating the listen address as necessary. Until the sca module doc on kamailio.org gets updated, you can find the sample configuration in the git master branch, or view it through gitweb at the link below. Best, andrew <http://git.sip-router.org/cgi-bin/gitweb.cgi?p=sip-router;a=blob_plain;f=modules/sca/doc/sca.cfg;hb=b8007d985660b4df5ea9d5ea4347adf65b7f90fa>