MCM Version 3.1

- Added "UNSOLICITED BULK EMAIL" as bounce subject when receiving mail.
- Increased (macro delimiter) field size from 64 to 256 characters.
- Added MCM_ALLOW_EMPTY_FIELDS. Allows recipient list fields to be empty.
- Allow insertion of files by use of @@filename in recipient list file.
- Set letter substitution delimiter to backquote or backslash with mcmSetInteger(MCM_SET_MACRO_DELIMITER, delimiter).
  Example: mcmSetInteger(MCM_SET_MACRO_DELIMITER, '`').
- Added mcmSetProxySSL(), which allows MCM to connect to servers requiring SSL.
- Added new merge code MCM_STAT_WITH_EMPTY_MACRO_STRING - macro (1st list line) is empty.
- Added new merge code MCM_STAT_WITH_EMPTY_LIST_STRING - entry in recipient list is empty.
- Added new stat code MCM_STAT_WITH_EMPTY_LIST_STRING - counts "MCM_STAT_WITH_EMPTY_LIST_STRING" errors.