Improved default value of BonjourAccount's display_name setting

Ignore-this: b66b46c3d60e8cbcb143ef665af8ed0b

darcs-hash:20100414122834-1e3d8-b1e9078474fbdb245b7ad8b688850d61fc106d31
Added support for authentication username

Ignore-this: 22e91331da027b281e1db1bd5dc2f0ed

darcs-hash:20100415085610-1e3d8-9f837b8d24e51d4a7a689d37929c03497d793f41