Email send fails if username/password are blank

If username/password is left empty, the app still tries to use them to authenticate against the mail server. Some mailservers are configured to accept anonymous sends from certain IP ranges and won't accept authentication from that range (read: I don't have a user that I'm willing to put credentials visible for, and my build server is allowed to anonymously send messages through our exchange server).

Relatively easy fix, if both the username & password are empty, don't try using them at all. Per the docs for SimpleEmail, authentication won't be used if .setAuthentication isn't called (http://commons.apache.org/email/apidocs/org/apache/commons/mail/Email.html#setAuthentication%28java.lang.String,%20java.lang.String%29)