Allow projects to turn on -ansi flag

    This is required for use of C++11 as it is not all supported under ansi

    Usage:
        To turn of ansi add the following to your Makefile
            THORSANVIL_ANSI_USE = OFF
Modified ANSI settings.

    If you turn on the C++11 flag then we no longer use -ansi
    By default we use C++03