Walk the user though the Wallace setup.

def setup():
    """Walk the user though the Wallace setup."""
    # Create the Wallace config file if it does not already exist.
    config_name = ".wallaceconfig"
    config_path = os.path.join(os.path.expanduser("~"), config_name)

    if os.path.isfile(config_path):
        log("Wallace config file already exists.", chevrons=False)

    else:
        log("Creating Wallace config file at ~/.wallaceconfig...",
            chevrons=False)
        wallace_module_path = os.path.dirname(os.path.realpath(__file__))
        src = os.path.join(wallace_module_path, "config", config_name)
        shutil.copyfile(src, config_path)