(struct CHISE_DS): Add new member `property_names'.

(struct CHISE_DS): Add new member `property_names'.
(CHISE_DS_open): Initialize `property_names'.
(CHISE_DS_close): Destroy `property_names'.
(chise_ds_location): New function.
(chise_ds_get_property): New function.
(struct CHISE_Property_Table): New structure.
(chise_ds_open_property_table): New function.
(chise_pt_close): Likewise.
(chise_property_setup_db): Likewise.
(chise_property_sync): Likewise.
(chise_feature_set_property_value): Likewise.
(chise_feature_load_property_value): Likewise.
(chise_feature_gets_property_value): Likewise.