blist help and behavior do not agree

[jgross@mit.edu]

:help blist says "List all buddies logged in" and "Print a listing of buddies logged in, regardless of protocol.". But only zephyr hides offline buddies; other protocols do not. One way or another, the help should agree with the behavior. One way to handle this is to add an option to blist which determines whether or not offline buddies are hidden, and update the protocols.