Allow extra Session properties configured through simplejavamail.properties

[bbottema]

Currently the only way to add properties to the underlying Session instance is by using the Java api myMailer.getSession().

It would be convenient to be able to configure default extra properties through the simplejavamail.properties file:

simplejavamail.extraproperties.this.is.the.actual.property=this is the value

Real world example that will soon be supported natively by Simple Java Mail:

simplejavamail.extraproperties.mail.smtp.ssl.socketFactory.class=org.mypackage.ssl.FIPSCompatibleMailSSLSocketFactory.class

[bbottema]

Released in 6.3.0.