Automatically convert plain lists into ObservableList in setters
Qualify observe.dart import; remove unused collections.dart import
Merge pull request #94 from yjbanov/auto-convert-lists

Auto convert lists; import clean-ups
Make frozen entity lists immutable.
Merge pull request #97 from alxhub/immutable-lists

Make frozen entity lists immutable.
Replace streamy SetMultimap with implementation from Quiver.