Updated m209 man page, which still referred to old obsolete file format.
Now looks for key table files with extension of either .txt or .m209key.
Extension of .txt is now preferred so that double-clicking a key file
on a DOS system opens it in a text editor by default.
Now looks for key table files with extension of either .txt or .m209key.
Extension of .txt is now preferred so that double-clicking a key file
on a DOS system opens it in a text editor by default.