MAIL -> booleandelto ( [ string address ] )
Return TRUE if has been successfully deleted, FALSE if not.
string address format is "localpart@domainpart.tld".
Example:
$m = new MAIL;
// add To mail address
$m->AddTo('localpart@domainpart.tld');
// delete To mail address
$m->DelTo('localpart@domainpart.tld');
// delete all To mail addresses
$m->DelTo();