XD-1193 Update to Spring Batch 2.2.4

Update to released GA version.

JIRA: https://jira.springsource.org/browse/XD-1193
XD-1188: Add ModuleOptionsMetadata for Rabbit sink

Also, factor out common options b/w sink and source

Also, minor tweaks to PojoModuleOptions type detection

Also, fix wrong MediaType in abstract classes (was harmless)