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/Layout/LayoutBlock.cpp

@@ -0,0 +1,28 @@
+#include <LibHTML/DOM/Element.h>
+#include <LibHTML/Layout/LayoutBlock.h>
+
+LayoutBlock::LayoutBlock(const Node& node, const StyledNode& styled_node)
+    : LayoutNode(&node, styled_node)
+{
+}
+
+LayoutBlock::~LayoutBlock()
+{
+}
+
+void LayoutBlock::layout()
+{
+    compute_width();
+
+    LayoutNode::layout();
+
+    compute_height();
+}
+
+void LayoutBlock::compute_width()
+{
+}
+
+void LayoutBlock::compute_height()
+{
+}