(chise_open_data_source): Add new arguments `subtype' and `modemask'.

(chise_open_data_source): Add new arguments `subtype' and `modemask'.
(chise_ds_get_feature): Delete arguments `real_subtype', `accessmask',
`modemask'.
(chise_char_feature_value_iterate): Return an integer value.
(chise_char_feature_str_iterate): Comment out.
(chise_ds_open_feature_table): Delete arguments `real_subtype',
`accessmask', `modemask'.
(chise_ds_get_ccs): Delete arguments `real_subtype', `accessmask',
`modemask'.
(chise_ccs_set_decoded_char): Renamed from `chise_ccst_put_char'.
(chise_ccs_sync): New prototype.
(chise_ds_open_ccs_table): Abolished.
(int chise_ccst_close): Abolished.