SMTP::Recipient

Sends the command RCPT to the SMTP server with the TO: argument of $to.

Returns true if the recipient was accepted false if it was rejected. Implements from rfc 821: RCPT <SP> TO:<forward-path> <CRLF> SMTP CODE SUCCESS: 250, 251 SMTP CODE FAILURE: 550, 551, 552, 553, 450, 451, 452 SMTP CODE ERROR : 500, 501, 503, 421