introduce CMAKE build

[bilaleluneis]

Hi Marc,

I pulled your project into my CLion IDE (IntelliJ), looks very interesting! great work there.. are you really 16 years old!!!

I have introduced a cmake file that would allow more portable and modern build approach and easy IDE agnostic integration. I am attaching it here. just drop it next to buildSo.sh. the cmake will configure two targets ( shared lib "mlpp" and mlpp_runner for your main.cpp that will link against the shared library). I also upped the C++ support to 20.
CMakeLists.txt