use new RootContextSource pattern

Author: burdo

src/main/java/org/comroid/api/func/ext/Context.java

@@ -342,7 +342,7 @@ class Base implements Context {
         }
 
         @Getter protected final Set<Context> children;
-        @Getter private final   Set<Object>  myMembers;
+        @Getter protected final Set<Object> myMembers;
         private final           Context      parent;
         private final           String       name;