Fixed a bug with variables in PGstatisticsGraphMacros.pl not being properly defined.
Merge pull request #11 from openwebwork/develop

Develop
Merge branch 'develop' into black_dev
Fixed the definition of pi in the PGstatisticsmacros.pl file.
Merge pull request #95 from KellyBlack/black_dev

Fix error in way variables are defined in PGstatisticsGraphMacros.pl