Fix trapped eval statements

Replace `veal` with `Parser::Eval()` to avoid it being trapped in safe compartment in some versions of perl.  This affects `compoundProblem5.pl` and `scaffold.pl`.  Apparently we need someone with an older version of perl to test this (before 5.10?).  You can use any scaffold problem (like the one in the comments of each file) to see that the answers are being properly evaluated for purposes of exposing the later parts of the problem.