Tessagon

This small release adds the `SvgAdaptor`, a component for creating an Inkscape extension.

You can checkout the nascent Inkscape extension here: <https://github.com/cwant/inkscape-tiling-extension>.

* An integration test that uses the main demo script (boosts the test coverage a lot)
* Improvements to how neighboring tiles are handling in type recipes.
* Non-convex tilings: Stanley Park, Islamic Hex and Stars, Islamic Stars and Crosses.
* More tiling types: Valemount, Cloverdale,
* More metadata: aspect ratio, which allows for rendering of nice looking 2D tilings (`simple_2d` option)
* "extra parameters" for Tessagon types (included in metadata). `WeaveTessagon` and `BigHexTriTessagon` have extra parameters.
* Mysterious `parallelogram_vectors` feature. It now drives the working of the `rot_factor` feature and allows for many possibilities (provided that you can figure it out)
* AlternatingTiles for specific types, and nascent rotational symmetry feature.
* Many refactorings of internal code

Added BigHexTriTessagon (the last Archimedean tiling).

* Added a bunch of color patterns
* Added a link to usage in Inkscape

Added:

* A `ListAdaptor` class to provide a generic, package-agnostic interface with other python software;
* A metadata and discover layer to help navigate and find tilings with certain properties;
* Update the readme to include some information about a recent presentation about tessagon.

A quick release to correct a few things with the PyPI packaging.