Option to select Contact List display style

[RDBoyce]

In the previous version, Adium only displayed the contacts that were actually online. I liked this option as anyone else that was invisisble would IM me when thye wanted to talk. With the new version displaying all the contacts at once, it id hard to keep track of who is online over multiple services. I know some folk like this; however, making it a configurable option would benefit everyone.

[evands]

Duplicate #7561