Representative value of parent should reset when a rep file is deleted

HYDRASIR-530 #close
Merge pull request #529 from projecthydra-labs/feature/530-reset-representative

Representative value of parent should reset when a rep file is deleted
Updating gemspec to work for hydra-derivatives
Merge pull request #530 from ndlib/hotfix-hydra-derivatives

Updating gemspec to work for hydra-derivatives
Merge branch 'develop' into update-article-metadata

* develop:
  Updating gemspec to work for hydra-derivatives
  Representative value of parent should reset when a rep file is deleted