Fixed: Correctly remove user from operator ranks when he deletes his own registration
Changed: User registration notification now rely on plugin callbacks instead of command scans
Added: Public user registration notification for all classes, empty regnewpubmsg* to skip notification for that class, idea by KCAHDEP
Added: cURL will use same local address for connections as hub itself when defined
Added: cURL helper function now returns response headers if requested
Added: Avdb-Version-Count and Avdb-Delete-Count extension headers to use with AVDB load process