Add luwra.h which includes all headers collectively

lib/luwra.h

@@ -0,0 +1,10 @@
+#ifndef LUWRA_H_
+#define LUWRA_H_
+
+#include "luwra/common.h"
+#include "luwra/types.h"
+#include "luwra/stack.h"
+#include "luwra/userdata.h"
+#include "luwra/wrappers.h"
+
+#endif