Refactor ingest controller tests

Should make it easier to test URI translation
Remove subject from factories

Since it's a controlled vocab field, this factory can cause endless
pain and suffering when tests fail due to the subject being invalid
Translate URIs into human-friendly values

- Adds class to check for properties that need to be translated
- Verifies that translation works in
- Fixes lots of tests that were using subject as if it weren't a
  controlled vocabulary field
Preload RDF labels instead of stubbing

Makes feature spec a little more real-world
Fix RDF-label-based intermittent test failures

Moves label preloading into test before(:each) blocks to (a) isolate
only those labels which need to be loaded, and (b) ensure the labels
are set in case other tests mess with the RDF repository.
Merge pull request #141 from OregonDigital/feature/translate-uris-in-ingest-edit

Feature/translate uris in ingest edit