zwicker-group/py-pde: 0.33.0

Release with minor improvements, but also some breaking of backwards compatibility. In particular, we made the definition of cell coordinates more precise, which previously was used inconsistently. Two different versions of cell coordinates have been used where integral coordinates either refer to the cell center or its left edge. We now define cell coordinates to use the latter, since then the integral part denotes the cell, while the fractional part denotes the position within the cell.

• Allow appending fields to field collection by @david-zwicker in https://github.com/zwicker-group/py-pde/pull/451
• Return shallow copy of fields in collection for safety by @david-zwicker in https://github.com/zwicker-group/py-pde/pull/452
• Allow disabling fancy progress bar by @david-zwicker in https://github.com/zwicker-group/py-pde/pull/453
• Remove outdated lgtm comments by @david-zwicker in https://github.com/zwicker-group/py-pde/pull/454
• Added support for solving Poisson's equation to cylindrical grids by @david-zwicker in https://github.com/zwicker-group/py-pde/pull/456
• Added support from complex fields in spectral operators by @david-zwicker in https://github.com/zwicker-group/py-pde/pull/457
• Allow dictionaries to initialize FieldCollection by @david-zwicker in https://github.com/zwicker-group/py-pde/pull/458
• Changed some comments and messages by @david-zwicker in https://github.com/zwicker-group/py-pde/pull/463
• Added mixed (Robin) boundary conditions with expressions by @david-zwicker in https://github.com/zwicker-group/py-pde/pull/464
• Improved some types and docstrings by @david-zwicker in https://github.com/zwicker-group/py-pde/pull/466
• Made definition of cell coordinates more precise by @david-zwicker in https://github.com/zwicker-group/py-pde/pull/467

Full Changelog: https://github.com/zwicker-group/py-pde/compare/0.32.2...0.33.0