Py-pde

What's Changed
* Improved output when trackers took a long time by david-zwicker in https://github.com/zwicker-group/py-pde/pull/347
* Improved documentation of plotting by david-zwicker in https://github.com/zwicker-group/py-pde/pull/348
* Updated version of sphinx-rtd-theme by david-zwicker in https://github.com/zwicker-group/py-pde/pull/349
* Updated logos by david-zwicker in https://github.com/zwicker-group/py-pde/pull/350
* Test scipy solver for field collections by david-zwicker in https://github.com/zwicker-group/py-pde/pull/352
* Fix matplotlib warning by david-zwicker in https://github.com/zwicker-group/py-pde/pull/356
* Improve error message when `numba_mpi` is not found by david-zwicker in https://github.com/zwicker-group/py-pde/pull/357
* Improved documentation by david-zwicker in https://github.com/zwicker-group/py-pde/pull/359
* Mostly improvements of documentation by david-zwicker in https://github.com/zwicker-group/py-pde/pull/361
* More detailed table of contents in PDF manual by david-zwicker in https://github.com/zwicker-group/py-pde/pull/362
* Protect `periodic` attribute of grids by david-zwicker in https://github.com/zwicker-group/py-pde/pull/363
* Improved operator handling by david-zwicker in https://github.com/zwicker-group/py-pde/pull/369
* Extended expression BCs to also accept python functions by david-zwicker in https://github.com/zwicker-group/py-pde/pull/370
* Improved check of functions setting BCs by david-zwicker in https://github.com/zwicker-group/py-pde/pull/371
* Added tighter check to dot product operator by david-zwicker in https://github.com/zwicker-group/py-pde/pull/373
* Generalized inner product operator by david-zwicker in https://github.com/zwicker-group/py-pde/pull/374
* Added additional checks to new implementation of operators by david-zwicker in https://github.com/zwicker-group/py-pde/pull/377


**Full Changelog**: https://github.com/zwicker-group/py-pde/compare/0.27.1...0.28.0

What's Changed
* Separate tests from code by david-zwicker in https://github.com/zwicker-group/py-pde/pull/343
* Moved additional requirements to tests folder by david-zwicker in https://github.com/zwicker-group/py-pde/pull/344


**Full Changelog**: https://github.com/zwicker-group/py-pde/compare/0.27.0...0.27.1

What's Changed
* Noise strength is now specified by the variance by david-zwicker in https://github.com/zwicker-group/py-pde/pull/342
* Add workflow to check whether documentation is built by david-zwicker in https://github.com/zwicker-group/py-pde/pull/340
* Allow using the actual evolution rate in the steady state tracker by david-zwicker in https://github.com/zwicker-group/py-pde/pull/341


**Full Changelog**: https://github.com/zwicker-group/py-pde/compare/0.26.0...0.27.0

Fix critical bug where version was not determined correctly

Completely revamped the build system to be more compact, flexible, and future proof