release v0.1

[keewis]

Since most of the originally planned features are implemented:

• CLI with checking and reformatting modes (#1)
• format registering with enabling / disabling of specific formats (#2, #18), including:
  • support for doctest
  • support for rST (including most of the special syntax of the ipython sphinx directive) (#10)
• file detection / filtering via include regex (#24)
• documentation (though it could use more attention) (#19)
• add community guide lines (code of conduct, contributor guides, templates).
  Maybe we can copy most of these from black?

we can think of publishing a alpha release to PyPI.