Moved the housekeeper heartbeat to a separate header for ease of integration.

This keeps the behavior the same but allows the heartbeat to be used as a crude timer
without including everything the housekeeper.h header includes.

Moved the protocol level updates on the DCBs last_read value into dcb_read.
This keeps the implementation nice and compact.

server/include/hk_heartbeat.h

@@ -0,0 +1,11 @@
+#ifndef _HK_HEARTBEAT_H
+#define _HK_HEARTBEAT_H
+
+/**
+ * The global housekeeper heartbeat value. This value is increamente
+ * every 100ms and may be used for crude timing etc.
+ */
+
+extern unsigned long	hkheartbeat;
+
+#endif