The initializer tests verify that every non-optional initializer, this
includes Providers, is loadable.
Creating files under META-INF is not considered best practice. Smack's
configuration and provider files reside now in classpath directory
qualified by Smack's package namespace.
If a Manager is strong referenced from a gc root, usually the instances
map, it should not hold itself a strong reference the connection in
order to avoid a cycle that prevents the Connection instance from being
gc'ed.
SMACK-383
