Fixed performance bug in UIOP:DIRECTORY-FILES

I bumped ASDF to 3.1.7.1 after I fixed a performance bug in directory-files that made it quadratic instead of linear, due to some remove-duplicates used for logical-pathnames. The fix was to only use this quadratic behavior for LPNs. If you use LPNs, you deserve to lose on large directories. LPNs are for legacy Lisp code with relatively few files, only.

—♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics• http://fare.tunes.org The best of all regimes is one where I am the head honcho of a worldwide empire. — Winston Churchill (his most famous quip, as translated to plain English)