[zfcampus/zf-apigility-skeleton#37] Fix reported issue

- Wrote test to confirm issue reported (`is_collection` was being overwritten on
  save)
- Wrote patch to fix the issue (wrote checks to only update if data is
  different; always add key into update array as the operation being called
  replaces the key)
Merge branch 'hotfix/skeleton-37'

Fixes zfcampus/zf-apigility-skeleton#37