Add option: separator for all fields (e.g. tab)

[f2d]

Not a mission-critical enhancment, but some of advantages are:

• Lists will look a bit more aligned without need to count symbols.
• Won't need any other separator, only to specify what optional fields are enabled.

I normalize all whitespaces to a single simple space in my served filenames anyway.
And I don't think I've ever seen a file with a tab in filename, not fabricated specifically to show off some bug somewhere.