Version 0.8.x Release Notes

[ChatGPT summary] Between versions 0.8.0 and 0.8.4, the python-control package introduced significant updates and enhancements. Notable additions include improved support for nonlinear systems with a new input/output systems module and functions for linearization and differential flatness analysis, the ability to create non-proper transfer functions, and support for dynamic prewarping during continuous-to-discrete system conversion. Visualization improvements were made across several functions, such as enhanced options for Nyquist plots, better pole-zero mapping compatibility with recent matplotlib updates, and LaTeX formatting for Jupyter notebook outputs. Bugs were fixed in critical areas like discrete-time simulations, forced response computations, and naming conventions for interconnected systems. The release also focused on expanded configurability with a new use_legacy_defaults function and dict-based configuration handling, updated unit testing (switching to pytest), and enhanced documentation and examples, including for sisotool and trajectory planning. Improvements to foundational algorithms, such as pole placement, transfer function manipulation, and discrete root locus, rounded out this series of releases, ensuring greater flexibility and precision for control systems analysis.