XMLRPC notifications: more formats

the command line switch -x allows tho choose between several XMLRPC formats:

  * format 0 is the legacy SEMS di for the SBC application
  * format 1 only includes the call-id:
```xml
<?xml version="1.0" encoding="UTF-8"?>
<methodCall>
<methodName>teardown</methodName>
<params>
<param><value><string>${call-id}</string></value></param>
</params>
</methodCall>
```