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/CSS/StyleValue.cpp

@@ -0,0 +1,10 @@
+#include "StyleValue.h"
+
+StyleValue::StyleValue(Type type)
+    : m_type(type)
+{
+}
+
+StyleValue::~StyleValue()
+{
+}