Hi all,

I hope it is not to late for this but I'd like to have this modification
pushed.  This changes the field name from 'last-modified to 'modified
(the symbol for `bookmark-sort-flag' is kept to 'last-modified).

I think it make more sense since the "last" in 'last-modified refers to
the order (ie. the most recently modified will be first).  Afterward,
I'd like to introduce a 'created field too.

Best regards,