Get information about the API
        http://docs.opsview.com/doku.php?id=opsview4.6:restapi#api_version_information

def api_version(self, verbose=False):
        '''
        Get information about the API
        http://docs.opsview.com/doku.php?id=opsview4.6:restapi#api_version_information
        '''
        return self.__auth_req_get(self.rest_url, verbose=verbose)