added Environment for MPI initialization
This MR replaces the old AMDiS::init() - AMDiS::finalize() pattern with a RAII class Environment, to be instantiated at the begin of the main method, i.e.
int main(int argc, char** argv)
{
Environment env(argc, argv);
// get MPI rank and size from environment after instantiation:
std::cout << Environment::mpiRank();
std::cout << Environment::mpiSize();
}the ``finalize'' is called automatically when env is destructed, i.e. at the end of main().
Edited by Praetorius, Simon
