Fixed SIPAddress to encode '@' chars in username

Ignore-this: 6c3156fffe825ad0bb5137452fb7ca12

darcs-hash:20090317162836-1e3d8-c7f676e7965c0e2a9b5588593ee4f5b01e9cff20
make --trace-engine option ignore SIPTrace events

darcs-hash:20090318073359-b2873-f02618c3a8b4c22ee9653f52301a539d367485b5