Fix parserFunctionPrime.pl to handle names with primes properly in perl output (needed for answer checking, but not for display).  Apparently this file never worked (argh).
Don't force functions to be of class parser::FunctionPrime (this messed up teh differentiation, since parser::FunctionPrime has parent parserFunction, and that overrides the D method).
Add a missing semicolon
Merge pull request #137 from dpvc/patch-primes

Fix parserFunctionPrime.pl to avoid error during answer checking.