Setting ``send to me too'' operation

Beginning with version 8.10, sendmail includes by default the (envelope) sender in any list expansions. For example, if ``mary'' sends to a list that contains ``mary'' as one of the members, she will get a copy of the message. If the MeToo option is set to FALSE (in the configuration file or via the command line), this behavior is changed (that is, the sender is excluded in list expansions).