Implement rootsimcc in C++

[Piccions]

I strongly believe that the code implementing our custom compiler, and possibly also the additional libraries linked with the model code, should be implemented in C++. For example, for the compiler we are reinventing the wheel (see the vector datatype, the dynamic string). Let's discuss it!

[alessandropellegrini]

I sadly have to agree. Given the last discussion on the refactor of the repos, it can also be the opportunity to introduce proper C++ bindings and libraries here.

But we better stick to a "C+STL" form of C++ as much as possible.