Use only JMS/GroupExclusion if groups are there

When no groups are given in the ApiDoc, there should be no GroupExclusion and the Entity should be parsed wihtout exclusions.

Otherwise only the "Default" group of the Entity would be parsed, which may not be used.

The ApiDoc should not enforce the Entity to be grouped with "Default", to generate a "full-view" of it.
Merge pull request #304 from h4cc/patch-2-squashed

Use only JMS/GroupExclusion if groups are there