Container: abort traversal with false return value of processor

So far, returning false from the processor function, just skipped further traversing the current child (depth-wise).
Now, traversal is completely aborted, even not traversing the remaining siblings of the current child.
Having a single boolean return value, we cannot distinguish both cases.
We need the new behaviour for 8061945c15bea22e8f8899c987bc28e3542885aa.

Author: rhaschke

core/include/moveit/task_constructor/container.h

@@ -54,6 +54,8 @@ class ContainerBase : public Stage
 	size_t numChildren() const;
 	Stage* findChild(const std::string& name) const;
 
+	/** Callback function type used by traverse functions
+	 *  The callback should return false if traversal should be stopped. */
 	typedef std::function<bool(const Stage&, int depth)> StageCallback;
 	/// traverse direct children of this container, calling the callback for each of them
 	bool traverseChildren(const StageCallback& processor) const;

core/src/container.cpp

@@ -81,7 +81,7 @@ bool ContainerBasePrivate::traverseStages(const ContainerBase::StageCallback& pr
 
 	for (auto& stage : children_) {
 		if (!processor(*stage, cur_depth))
-			continue;
+			return false;
 		const ContainerBasePrivate* container = dynamic_cast<const ContainerBasePrivate*>(stage->pimpl());
 		if (container)
 			container->traverseStages(processor, cur_depth + 1, max_depth);