Release 0.1.0

It’s about time we had a release so that we can move towards making Mismiy installable, which in turn would make it possible to provide instructions for setting up a blog that are less primitive.

To that end I have been drafting a more extensive readme and creating a changelog. The format of the latter is broadly based on the suggestions in Keep a Changelog. I have dithered for a bit over whether to call this version 0.1.0 or 1.0.0. I think for now I plan to reserve the latter for when I have something I think makes sense to upload to PyPI.