Closes #279.

Closes #214.

Raise a TypeError when site sizes/colors are provided as arrays
and the system to plot is a kwant.Builder.

Closes #293

See merge request kwant/kwant!301

Raise a TypeError when a site size/color is provided as an array
and the system is a kwant.Builder, as the site ordering for the
latter is not well defined. A function should be used instead.

Closes issue #299

Closes issue #300

Convert tutorial building machinery to Jupyter-Sphinx.

Closes #87

See merge request kwant/kwant!296

Currently we just set the default figure size. Matplotlib is
annoying when it comes to setting these default parameters, and we
have to ensure that we set any 'rcParams' in a separate Jupyter cell
and *after* we import pyplot.

Use a more modern sphinx invocation

Closes #295.