Added sample of outline index file.
Merge branch 'master' into outline
Merge branch 'master' into outline
Moved `edit` after `remove`.
Added integration tests.
Enabled CI.
Cleanup.
Updated logging.
Implemented manual reordering.
Added unit tests for manual reordering.

Also fixed typo: MAX_LINE_LENTH => MAX_LINE_LENGTH
Updated TODOs.
Fixed handling of bad YAML.
Added handling for unknown IDs.
Added a message for invalid YAML.
Using document's starting level.
Added a missing test.
Merge pull request #111 from jacebrowning/outline

Use `index.yml` to manually reorder item levels.
Merge branch 'master' into gui