ZF-10758: Support StartTLS for sending Mails via SMTP


Zend_Mail_Protocol_Smtp supports SSL and TLS, but not StartTLS (see contrstructor of Zend_Mail_Protocol_Smtp)

More information about StartTLS * * *


My SMTP pipelining patch (ZF-8528) implements parsing of the EHLO keywords which would allow detection of STARTTLS support. Awaiting application of ZF-10741 to trunk and then I will refactor ZF-8528 out to split out a patch specifically for EHLO keyword parsing. Then this one will be easier to implement.