Requiring path on exclude tag for issue #32
#30 - Can now include paths in addition to excluding paths. Including
a subset of paths will exclude all others.
#31 - Renamed SkipValidation and exclude XML elements to better
indicate that they apply only to recursive sub-bean validation
#33 - Excludes from XML are now correctly excluded when validating
sub-classes as well.
#34 - Ensuring that errorPath is updated appropriately 
during recursive & collection validation.