ZF-9921: Zend_Mail: Allow multiple ReplyTo addresses
Multiple setReplyTo()-calls are currently prohibited and throw an Exception. This is unneeded, as the RFC822 (and the superceeding RFC2821) allow more than one reply-to header.
I added the capability to add multiple reply-to headers to the Mail.php code, as this was a feature I needed. I tried to stay in your coding-style, please consider this as an addition to your framework.
I propose the renaming to addReplyTo(), this would also be in style with addTo() etc.
Please find attached the modified Mail.php
PS: I also fixed ZF-2219 while I was at it (addBcc() lacks 'name' parameter).