Added support for printing notifications in sip_register

Ignore-this: 24ebbd1817f0760fb5a8596b182fca81

darcs-hash:20090406124513-1e3d8-39ca13c39e694e6206bbcc548367df277f1e4ab5
Added support for notification tracing toggling in sip_register

Ignore-this: a778868ec51751bbd1a01cd4296139ca

darcs-hash:20090406130000-1e3d8-7c9e9ade4d4fe02486c5a3b38b0fff410729a345