MINOR: lua: core: add sleep functions

This version of sleep is based on a coroutine. A sleeping
task is started and a signal is registered. This sleep version
must disapear to be replaced by a version using the internal
timers.
diff --git a/include/types/hlua.h b/include/types/hlua.h
index 20ee080..f21f4e1 100644
--- a/include/types/hlua.h
+++ b/include/types/hlua.h
@@ -93,4 +93,11 @@
 	struct sample_fetch *f;
 };
 
+/* This struct contains data used with sleep functions. */
+struct hlua_sleep {
+	struct task *task; /* task associated with sleep. */
+	struct list com; /* list of signal to wake at the end of sleep. */
+	unsigned int wakeup_ms; /* hour to wakeup. */
+};
+
 #endif /* _TYPES_HLUA_H */