Many fixes & refactoring & add Quaternions

- add QuaternionWidget
- remove old modal code
- remove Copy and clone of AronTreeWidgetItem
- add recognition of duplicate dict keys
- add countermeasure to tabbing into unchangeable key fields
- make aronType const in AronTreeWidget
- flag tuple code as untested, since aron is currently broken there
- fix weird std::locals setting in AronTreeWidgetSetter.cpp, which causes floating numbers to print as 12,345 with std::to_string()
- add usage of std::launder to make reinterpret_cast more save within the usage of NDArray