This makes Smack more portable, as there are platforms that support the
XmlPullParser interface, but not MXParser (e.g. Android).
Also enable checkstyle check that MXParser is not used.
Change all \r\n into unix style newlines. Add missing newlines at the
end of a file and activate the newline checkstyle module, that enforces
'\n' as newline and a newline at the end of every file.
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.