Improve some relationship names
Improve some relationship names

* Use lowerCamelCase instead of alllowercase for relationship names,
  such as `master.importGroup`.
* Use 's' suffix instead of '_collectin' for many-to-one
  relationships, such as `master.versions`.
* Use custom names for for some relationships, such as
  `master.originalVersion`.

staticshock/iphoto.py