VOL-44, VOL-55: Created new contact subtype Volunteer and an example custom field for same. Includes both install and upgrade code.
VOL-44, VOL-56: Created new profile for volunteer interest form. Includes both install and upgrade code.
Incorporated MZD feedback on function names and error messages. Added code comments.
Merge pull request #191 from GinkgoFJG/VOL-44

VOL-44, VOL-55: Created new contact subtype Volunteer and an example cus...