rstcheck-3.1-bp151.3.1

- bump to verion 3.1
- Add support for checking XML code blocks (thanks to Sameer Singh).
- Support UTF-8 byte order marks (BOM). Previously, ``docutils`` would
  interpret the BOM as a visible character, which would lead to false
  positives about underlines being too short.
- Optionally support Sphinx 1.5. Sphinx support will be enabled if Sphinx is
  installed.
- Support loading settings from configuration files.

- Update dependecies

- bump to version 1.5.1
- turn off building for python2
- check spec file with spec cleaner

- rstcheck-1.4.1

- rstcheck-1.3.1