ERT-710 / RO-12: Added method gen_kw_data_has_key()
ERT-710 / RO-12: Added possibility to create an empty gen_kw_config(), and added method set_parameter_file() to be able to populate the empty instance
ERT-710 / RO-12: Added fault handling
ERT-710 / RO-12: Made test independent of StatoilData, added some more fault testing