Libraries: Create top level directory for libraries.

Things were getting a little crowded in the project root, so this patch
moves the Lib*/ directories into Libraries/.

Libraries/LibCore/CObject.h

@@ -0,0 +1,94 @@
+#pragma once
+
+#include <AK/Function.h>
+#include <AK/StdLibExtras.h>
+#include <AK/Vector.h>
+#include <AK/Weakable.h>
+
+class CEvent;
+class CChildEvent;
+class CTimerEvent;
+
+class CObject : public Weakable<CObject> {
+public:
+    CObject(CObject* parent = nullptr, bool is_widget = false);
+    virtual ~CObject();
+
+    virtual const char* class_name() const { return "CObject"; }
+
+    virtual void event(CEvent&);
+
+    Vector<CObject*>& children() { return m_children; }
+    const Vector<CObject*>& children() const { return m_children; }
+
+    template<typename Callback>
+    void for_each_child(Callback callback)
+    {
+        for (auto* child : m_children) {
+            if (callback(*child) == IterationDecision::Break)
+                return;
+        }
+    }
+
+    template<typename T, typename Callback>
+    void for_each_child_of_type(Callback callback);
+
+    CObject* parent() { return m_parent; }
+    const CObject* parent() const { return m_parent; }
+
+    void start_timer(int ms);
+    void stop_timer();
+    bool has_timer() const { return m_timer_id; }
+
+    void add_child(CObject&);
+    void remove_child(CObject&);
+
+    void delete_later();
+
+    void dump_tree(int indent = 0);
+
+    void deferred_invoke(Function<void(CObject&)>);
+
+    bool is_widget() const { return m_widget; }
+    virtual bool is_window() const { return false; }
+
+protected:
+    virtual void timer_event(CTimerEvent&);
+    virtual void child_event(CChildEvent&);
+
+private:
+    CObject* m_parent { nullptr };
+    int m_timer_id { 0 };
+    bool m_widget { false };
+    Vector<CObject*> m_children;
+};
+
+template<typename T>
+inline bool is(const CObject&) { return false; }
+
+template<>
+inline bool is<CObject>(const CObject&) { return true; }
+
+template<typename T>
+inline T& to(CObject& object)
+{
+    ASSERT(is<typename RemoveConst<T>::Type>(object));
+    return static_cast<T&>(object);
+}
+
+template<typename T>
+inline const T& to(const CObject& object)
+{
+    ASSERT(is<typename RemoveConst<T>::Type>(object));
+    return static_cast<const T&>(object);
+}
+
+template<typename T, typename Callback>
+inline void CObject::for_each_child_of_type(Callback callback)
+{
+    for_each_child([&](auto& child) {
+        if (is<T>(child))
+            return callback(to<T>(child));
+        return IterationDecision::Continue;
+    });
+}