Allow passing of user emailaddress

[tcurdt]

In previous versions there was a reportAsUser:NSSTRING method, which seems to be gone. It would be great if we could still pass an emailaddress to FeedbackReporter, so that the user don't has to enter it (which will include typos anyway) if the application already knows about the users emailaddress (which is the case in many applications - for instance if it is used as the users "account" etc).