Update harmony.ScaleDegreeIndexer to Return key.KeyIndexer Results Too

Without a key, scale degrees are meaningless. Since the next step will
invariably require considering KeyIndexer along with scale degrees, we
might as well just send them all together.
WorkflowManager Regression Fix

In commit 5ddcec58aa9bce5b03b030e4d6022b49c3cfdb59 I accidentally changed
an iterkeys() call to itereach_keys() because of a sloppy find-and-replace
and then failing to run the automated tests. Oops.
Modify WorkflowManager and lilypond.LilyPondIndexer to Work Together

- add "LilyPond" instruction to WorkflowManager.output()
   - rearrange output() slightly (mostly dedent) to share some checks
     between output() formats
   - one test for output() fails because of the rearrangement; I'll keep
     it failing until we have proper test revisions
- LilyPondIndexer accepts an annotation part in the settings
Correct Test for ScaleDegreeIndexer