A multitude of adjustments

- Use docutils to do the rst file parsing and use the
  results of its parsing to do the max line length analysis
  on. This ensures that we do not create our own rst parser
  in doc8 but use a more hardened an mature one instead.
- Allow long-titles to be excluded from the max line length
  checks by allowing a CLI or config option to be provided
  that specifies this.
- Allow the ignored errors to be provided on the CLI.
Bump to 0.2.0
Rename split_uniq_string -> split_string
Rename find_nodes and fix issue with line < first_line