cobmysqlapi.c for 1.xx and 2.xx

Finally the new version of cobmysqlapi.c, which can handle both GnuCobol 1.xx and 2.xx has passed the first tests (and so did my test program PCTB003B).

Which means, a few more tests with both compiler versions and maybe writing a little bit more of documentation, and we can have another release of dbpre soon.