Revision 3571

Load Parser::Legacy.

This change is needed for the current version of extraAnswerEvaluators.pl
to work out of the box.  By default, one will still get the original
(non-Parser) versions of num_cmp and fun_cmp, but turning on the
Parser-based versions will be much easier (just one line to change, or
override on a course by course basis).

There will be a companion change in the pg directories.