scalaz/scalaz — pull request #253 by S11001001 (2013-01-14 16:57:39+00:00)
Title: Specialize foldLeft for NonEmptyList; foldLeft/foldLeft1 for Tree.

While NEL provides a specialized `foldLeft1`, the derived `foldLeft` doesn't use this. Here we specialize the `foldLeft`/`foldLeft1` for both `Traverse1` instances.