Nielsen

Add a `--(no-)fiter` option to toggle series filtering behavior at runtime.

Fix dry-run functionality and add `dryrun` parameters to both the `process_file` and `organize_file` functions in the API.

Support detection of filenames of the format: `Firefly 0101 - Serenity.mkv`.

Add the ability to customize the format of the filenames `nielsen` writes with
the following tokens: `{series}`, `{season}`, `{episode}`, `{title}`,
`{extension}`.

The `format` option can be defined in the `Options` section of the
configuration file (`nielsen.ini`) or set in the `CONFIG` object itself.

Add support for `pathlib` and use it to handle generating file paths
and extracting information from them rather than `os.path`.

Favor returning `Path` objects from API functions that modify files in
some way.

Add a `nielsen.files` module which handles most of the underlying file
operations (making calls out to `shutil` for things like `chown` and
`move`).

Change the date format precision in logs to seconds (from milliseconds).

Rename 'filter_filename` to `sanitize_filename` and add a `system_type`
parameter to change which OS type it will sanitize the filename for.

Rename `titles` module to `tv`.

Move the CLI to its own module (`bin/cli.py`) rather than being part of
the `api` module.

Make "interactive" mode optional.