WINDUP-104: Fix/standardize POM structure and simplify project layout

Ready for review.
If we are going to make IMPLICIT a default, I really think this should only happen if both executeBefore and executeAfter are specified. Otherwise, it is entirely possible for the rule to execute at the very beginning (before any real initialization) or at the extreme end (after all reporting and finalization). I don't think that anyone would want either of those scenarios. :)