Add STARTTLS

[tobiasBora]

Hello,

First, thanks for this great module. However, it seems that STARTTLS is not supported out of the box, while it should be pretty easy to configure it, as it's just a new parameter to give to Imap(...) which is autotls that should be equal to always when the user wants to enable STARTTLS (default: never). Would it be possible to do this simple change?

Thanks!