[feat req] more flexibility in display time

[Xiong Chiamiov]

It usually takes me at least 10 seconds to realize that a new song is playing, and by then the growl notification is gone. I'm using Pandora (and a last.fm extension that sends song notifications to growl), so I can't have the player show some sort of on-screen display. The extension provides track information in my browser window, but I'm frequently on a virtual desktop that doesn't have one open.