* 🚸 add error message if test suite cannot be found Fixes #3584
* 📄 add licenses * 👷 add REUSE compliance check * 📝 add badge for REUSE Co-authored-by: Florian Albrechtskirchinger <falbrechtskirchinger@gmail.com>
Use DOCTEST_* macros in place of predefined compiler macros for compiler detection and version checks. The suppression of warning -Wrange-loop-construct in unit-items.cpp causes GCC<11 to warn about pragmas. Suppressed by adding a version check.
* 🚚 move files * 🚚 rename doc folder to docs * 🚚 rename test folder to tests
