Adding pg paths to hardcopies

One of our professors complained that hardcopies in one course would show the PG path per problem and in another course they wouldn't.  The previous admin would set $pg{specialPGEnvironmentVars}{PRINT_FILE_NAMES_FOR} to a static list of the admin names in each course.  Not very happy with this, I tracked this down to this missing option in the hardcopy generation code.  With it added, professors get the file path added to each problem when they request a hardcopy.

This is a re-submit of the previous pull request against develop.