Choke not on nameless uses.
Don't require a name when emitting uses.
A whole bunch of progress on ScalaExtractor.

It was looking pretty bleak there for a bit, but I think I'm to the point where
enough is working that it'll be worth the trouble to soldier on. I may never
get the Scala AST to report everything correctly, but I'll take what I can get.
Added Lang.isRoot().

I want to do this differently in the future, but it's useful for now.
Break apart super linearization and member resolution.

In some cases we want to know the linearized supertypes in addition to the
members so that we can group the members by defining type.