Supply additional labels for new github issues

Provide an array of labels to be added to the ParyFoul standard labels
that are added to new GitHub issues.  Also accepts a Proc that is passed
the exception and the env to make labeling decisions
Keep existing labels on re-opened issues
fix typo in generated initializer file
Merge pull request #27 from smartlogic/custom_labels

Supply additional labels for new GitHub issues
Merge pull request #28 from smartlogic/existing_labels

Keep existing labels on re-opened issues