v0.5 release

New in this release:

• Added more preprocessing functions for importing data from a variety of different instrument vendors (Autolab, BioLogic, Gamry, Parstat, Powersuite, VersaStudio, ZPlot, ...) <-- huge thanks to @lktsui and @BGerwe 🚀 🚀
• @BGerwe improved documentation of the Gerischer element (⚠️ breaking change!)