DOC: API doc output to _build/api_doc
DOC: API doc output to _build/api_doc

...rather than at the same depth as the directory _build.  The goal is to
have all generated documentation under _build/.

tulip-control/tulip-control,necozay/tulip-control,necozay/tulip-control,tulip-control/tulip-control,necozay/tulip-control,necozay/tulip-control,tulip-control/tulip-control,tulip-control/tulip-control,necozay/tulip-control