add register-proxy option to gateways so you can send outbound reg to your local proxy dest for the outside

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@5713 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/mod/endpoints/mod_sofia/mod_sofia.h

@@ -196,6 +196,7 @@ struct sofia_gateway {
 	char *register_proxy;
 	char *register_context;
 	char *expires_str;
+	char *register_url;
 	uint32_t freq;
 	time_t expires;
 	time_t retry;