* Did most of the migration from save_message() to CtdlSaveMsg(). The

* Did most of the migration from save_message() to CtdlSaveMsg().  The
  latter builds a "struct CtdlMessage" (so we can run server-side handlers
  against it later on), then serializes it and stores to disk.
* BROKEN BUILD ALERT!!  cmd_ent3() and CtdlWriteObject() are still not
  migrated.  They are stubbed out and will MALFUNCTION if used right now!!