Some OutputLilyPond Submodule Commit Thing
Corrected OffsetIndexer, Which Returned a DataFrame

There was a reason to return a DataFrame: if all the Series have the same
index, then why not? But it broke the API, which says Indexer.run()
will return a list of Series.

(cherry picked from commit 893480b839930a90af500203eda1faaa4b500766)