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/LibHTML/DOM/Node.cpp

@@ -0,0 +1,11 @@
+#include <LibHTML/DOM/Node.h>
+#include <LibHTML/Layout/LayoutNode.h>
+
+Node::Node(NodeType type)
+    : m_type(type)
+{
+}
+
+Node::~Node()
+{
+}