Upgrade to libUseful-4. Compiles under osx. Verbose mode has 'hash-time' value.

Upgraded to libUseful-4. Compiling under macosx no longer fails with complaints about xsetattr (unless you try turning xattr feature on). using -v to set verbose mode prints out a hash-time value within the standard output format (so not 'trad' or 'bsd' formats) saying now long it took to hash each file.