INT-3531 Varargs for JavaMailSender

JIRA: https://jira.spring.io/browse/INT-3531

JavaMailSender now uses varargs instead of [].

Also, add spring-context-support as an optional
dependency to avoid reactor pulling in an old version into
the eclipse .classpath.

You cannot exclude transitive dependencies from optional
(reactor) dependencies.
I think it's OK. Since we are going to be a part of Boot 1.2, which will be based on SF 4.1.2.
So, LGTM - merging...