Indicate a .bakfile's number when invoking command

[ChanceNCounter]

If I've just done bak diff foo.cfg, I've just seen the selection menu for foo.cfg. I don't need it to come up again when I run bak down foo.cfg. I should be able to do bak down 2 foo.cfg (slightly less intuitive) or bak down foo.cfg 2 (riskier) to skip the dialog and restore that .bakfile. Since they're always sorted by "last modified"/"last restored" (#37) they're guaranteed to display the same number on the next invocation (assuming you haven't done a bak up in the meantime.)