cannot detect if output is tty in parallel

Actually in parallel:

• std::cout always believes it is a tty (even when redirected to a file)
• std::cerr always believes it is not a tty (even when not redirected to a file)

This has two implications with mpi runs:

• no colors for std::cerr, which is just sad
• cannot detect if application should be automatically paused when crashing in interactive mode