Dev tp

1. Project groups
2. Fix build in alib2gui on debian systems (jsoncpp)
3. Fix jsoncpp find_package in cmake
4. CMake 3.9 -> 3.7 -> build on debian stable is ok
5. CI: try build&test on various distributions (https://gitlab.fit.cvut.cz/algorithms-library-toolkit/automata-library/pipelines/23807)

changed the description

added 7 commits

• 0cc24eab...02f062cf - 2 commits from branch master
• 6816cd62 - CMake generator: Project groups
• 951e2f9c - CMake: fix jsoncpp includes
• a1c00ddb - alib2gui: Fix build on debian:testing
• fe7c02b8 - CMake: Compatibility with CMake 3.7
• 00c3393d - CI: Compatibility builds on debian/arch

Compare with previous version

enabled an automatic merge when the pipeline for 00c3393d succeeds

merged