Iterates through our parsed configuration options and cast any options with marked cast types.

def _cast(self):
        """
        Iterates through our parsed configuration options and cast any options with marked cast types.
        """

        for configName, configDict in self.configs.items():
            if configDict['cast'] is not None:
                configValue = getattr(self._config, configName)
                if configValue is not None:
                    try:
                        self._setConfig(configName, configDict['cast'](configValue))

                    except:
                        raise InvalidConfigurationException("%s: %r" % (configName, configValue))