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.
INT-3529 Add 'expire-groups-upon-timeout' to Reseq

JIRA: https://jira.spring.io/browse/INT-3529

Late arriving messages will now be immediately discarded by
default.

INT-3529 Polishing

Move group completion to the Resequencer's `afterRelease()` when
the group is timed out.