Fix confusion of new users regarding db files.

Now, we're using a different file extension for every db file
type. That way, if the user tries another file type and forgets to
specify a filename, the default is NOT to use the same one as before,
but another file. That way the message "file is encrypted" will not
appear anymore, if a new user follows the above steps.

lib/NOTEDB/binary.pm

@@ -5,7 +5,7 @@
 #
 package NOTEDB::binary;
 
-$NOTEDB::binary::VERSION = "1.12";
+$NOTEDB::binary::VERSION = "1.13";
 
 use strict;
 use IO::Seekable;