fix #615. adding contact to existing household, and specifying Address Override = true, gets error on save. No error if Address Override = false.
fix  #478. As an Admin, verify I am not allowed to create duplicate payment mappings
Merge pull request #621 from SalesforceFoundation/feature/sprint13-misc-fixes

fix #615. adding contact to existing household, and specifying Address O...
Merge dev into feature/340-contact-merge