func (m *Mason) RegisterConfigConverter(name string, fn ConfigConverter) error {
	_, ok := m.configConverters[name]
	if ok {
		return fmt.Errorf("a converter for %s already exists", name)
	}
	m.configConverters[name] = fn
	return nil
}
func (m *Mason) RegisterConfigConverter(name string, fn ConfigConverter) error {
	_, ok := m.configConverters[name]
	if ok {
		return fmt.Errorf("a converter for %s already exists", name)
	}
	m.configConverters[name] = fn
	return nil
}
// RegisterConfigConverter is used to register a new Masonable interface
// In: name - identifier for Masonable implementation
//     fn   - function that will parse the configuration string and return a Masonable interface
//
// Out: nil on success, error otherwise