Changes

Adds the fake smtp server and resolves minor bugs
Fake smtp server is necessary to check the sending of emails from the 
wildfly server. The script fake_smtp.sh has been added to automatice the
download and the execution of fakeSMTP-2.0 server. Besides, .jar and
.zip files used by this script have been added to .gitignore. Steps for
use this script have been added to CONTRIBUTING.md. The standalone.xml
has been modified to support the smtp connection. The pom.xml has been
modified to automatice the use of smtp server by testing servers. 
Finally, Mail ejb has been modified to reference the mail session
resource created in the standalone.xml. tsk6 completed.