* Add pyspelling configuration

Requires Py3k and:
$ conda install --channel conda-forge hunspell
$ pip install pyspelling
$ wget -O en_US.aff  https://cgit.freedesktop.org/libreoffice/dictionaries/plain/en/en_US.aff?id=a4473e06b56bfe35187e302754f6baaa8d75e54f
$ wget -O en_US.dic https://cgit.freedesktop.org/libreoffice/dictionaries/plain/en/en_US.dic?id=a4473e06b56bfe35187e302754f6baaa8d75e54f

* Add custom wordlist

* Document origin of doctest RE

* Clean up syntax to make pyspelling happy

* Ignore fenced multilines

* Ignore reST roles

* Ignore reST literals

* Make string raw for LaTeX backslashes

* Fix spelling errors in examples

* Ignore reST directives

* Fix capitalization

* Fix reST errors

* Remove obsolete functions

* Ignore generated files

* Pervasively switch to NumPy style docstrings

Ignored by .pyspelling.yml

* Fix things napoleon doesn't understand

* Document spell checking

* Add pyspelling to CI

* Ignore dictionary files

* Add spell check to CHANGELOG

* Switch to utf-8 encoding

* Convert leading tabs to spaces