- Remove now-removed configuration values
- Use obvious 'unset' defaults for ``project`` and ``author``
- Prefer 'e.g.' to 'ex.'
- Allow non-list sequence types in various configuration values
- Add types and defaults to every confval directive
A common "gotcha" of re-running `sphinx-autogen`, is that if there are changes it will not remove old files, leading to build errors for files not in a `toctree`
This commit introduces a `--remove-old` option to remove these files.
Note, a key detail here is that we don't want to simply clear the directory before running `sphinx-autogen`,
since this would lead to all files having a new `mtime`,
and then `sphinx-build` would rebuild all of them even if they have not changed.
So we must first collect the list of all correct files, then remove any not in the list.
