Added AP_Declination library. It contains the lookup table (lat/lng -> declination) as well as a method that performs the lookup.

Signed-off-by: Andrew Tridgell <tridge@samba.org>

libraries/AP_Declination/AP_Declination.h

@@ -0,0 +1,25 @@
+// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: t -*-
+
+#ifndef AP_Declination_h
+#define AP_Declination_h
+
+// Just incase it wasn't included elsewhere
+#include <avr/pgmspace.h>
+#include <math.h>
+
+/*
+ *	Adam M Rivera
+ *	With direction from: Andrew Tridgell, Jason Short, Justin Beech
+ *
+ *	Adapted from: http://www.societyofrobots.com/robotforum/index.php?topic=11855.0
+ *	Scott Ferguson
+ *	scottfromscott@gmail.com
+ *
+*/
+class AP_Declination
+{
+public:
+	static float get_declination(float lat, float lon);
+};
+
+#endif