Merge of all branches of Fabian PK (related to skills)

• Merge improved SkillManagerGUI from Tobias Bodmer
• Fix aron code generation for classes without members

@reister. YOu only need to review the changes to aron (Generator.cpp)

Depends on MR armarx-core!246 (merged)

Includes MR !285 (closed) and !320 (closed)

source/RobotAPI/gui-plugins/SkillManagerPlugin/aronTreeWidget/visitors/AronTreeWidgetConverter.cpp

@@ -64,7 +64,6 @@ namespace armarx
     AronTreeWidgetConverterVisitor::handleErrors(AronTreeWidgetConverterVisitor childV,
                                                  bool ownFault)
     {
-        // TODO debug this. Make target back to debugabble
         isDirectError |= ownFault;
         hasTransitiveError |= childV.isDirectError || childV.hasTransitiveError;
 
@@ -117,7 +116,7 @@ namespace armarx
             AronTreeWidgetConverterVisitor v(el, x);
             aron::type::visit(v, i->getAcceptedType());
             auto key = it->text(0).toStdString();
-            // TODO: handle key errors more elegantly / separately
+            // TODO: handle key errors more elegantly / separately, fine for now
             handleErrors(v, createdAronDict->hasElement(key));
             if (v.createdAron && v.isConversionSuccessful() && !createdAronDict->hasElement(key))
             {