Objects of this class are created to deal with memo files, currently .dbt, .fpt and .smt (code for this
provided by Dirk Tostmann). Package XBase::Memo defines methods read_header to parse that header of the
file and set object's structures, write_record and last_record to write the records properly formatted
and find the end of file.
There are four separate subpackages in XBase::Memo, dBaseIII, dBaseIV, Fox and Apollo. Memo objects are
effectively of one of these types and they override their specific record handling routines where
appropriate.