Skills: Optionals in manager gui

source/RobotAPI/components/skills/SkillProviderExample/aron/HelloWorldAcceptedType.xml

@@ -22,6 +22,9 @@
             <ObjectChild key='some_text'>
                 <String />
             </ObjectChild>
+            <ObjectChild key='some_optional_text'>
+                <String optional="True" />
+            </ObjectChild>
 
             <ObjectChild key='some_list_of_matrices'>
                 <List>