add multiple-registrations flag to the core similar to mod_sofia

conf/autoload_configs/switch.conf.xml

@@ -98,7 +98,9 @@
     <!-- <param name="core-db-name" value="/dev/shm/core.db" /> -->
     <!-- The system will create all the db schemas automatically, set this to false to avoid this behaviour-->
     <!--<param name="auto-create-schemas" value="true"/>-->
-	 <!-- <param name="core-dbtype" value="MSSQL"/> -->
+    <!-- <param name="core-dbtype" value="MSSQL"/> -->
+    <!-- Allow multiple registrations to the same account in the central registration table -->
+    <!-- <param name="multiple-registrations" value="true"/> -->
   </settings>
 
 </configuration>