JavaDoc
Merge pull request #155 from OndraZizka/GraphServiceJavadoc

JavaDoc
Logging.of() helper method.
Fix logging
    WINDUP-175  Shorten the WARN in DiscoverXmlFilesRuleProvider addXmlMetaInformation()
WINDUP-171 Use a constant instead of "type"
WINDUP-171 Use a constant instead of "type"
Add SLF4J to modules to see at least some logging.
Comment
WINDUP-156: Some simplifications to Iteration variable handling (implicit iteration variable names)