move AP_Var code and example into libraries/AP_Var

you can use AP_Var by defining USE_AP_VAR

libraries/AP_Common/AP_Common.h

@@ -38,8 +38,13 @@ typedef struct {
 #include "c++.h" // c++ additions
 //#include "AP_Vector.h"
 //#include "AP_Loop.h"
-#include "AP_Param.h"
 
+// default to AP_Param system, unless USE_AP_VAR is defined
+#ifdef USE_AP_VAR
+#include "AP_Var.h"
+#else
+#include "AP_Param.h"
+#endif
 
 ////////////////////////////////////////////////////////////////////////////////
 /// @name	Warning control

libraries/AP_Common/examples/AP_Var/Makefile

@@ -1,2 +0,0 @@
-BOARD	=	mega
-include ../../Arduino.mk

libraries/AP_Var/AP_Var.cpp

@@ -1,5 +1,3 @@
-#if 0 // we can't build this and AP_Param due to AP_Common.h conflicts
-
 // -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
 //
 // This is free software; you can redistribute it and/or modify it under
@@ -11,11 +9,10 @@
 /// @file   AP_Var.cpp
 /// @brief  The AP variable store.
 
-#define NO_AP_PARAM
+#define USE_AP_VAR
 
 #include <AP_Common.h>
 #include <AP_Var.h>
-
 #include <math.h>
 #include <string.h>
 
@@ -825,4 +822,3 @@ AP_Var_typesetup::AP_Var_typesetup(void)
 /// Cause the AP_Var_typesetup constructor to be run.
 ///
 static AP_Var_typesetup _typesetup __attribute__((used));
-#endif

libraries/AP_Var/AP_Var.h

@@ -943,7 +943,7 @@ extern AP_Float AP_Float_zero;
 extern void     AP_Var_print(AP_Var *vp);
 
 #ifndef __AP_COMMON_MENU_H
-# error Must include menu.h
+#include "include/menu.h"
 #endif
 
 /// Menu function for setting an AP_Var.

libraries/AP_Var/examples/AP_Var/AP_Var.pde

@@ -2,9 +2,12 @@
 // Unit tests for the AP_Meta_class and AP_Var classes.
 //
 
+#define USE_AP_VAR
 #include <FastSerial.h>
 #include <AP_Common.h>
 #include <AP_Test.h>
+#include <AP_Var.h>
+#include <AP_Math.h>
 #include <string.h>
 
 // we need to do this, even though normally it's a bad idea

libraries/AP_Var/examples/AP_Var/Makefile

@@ -0,0 +1 @@
+include ../../../AP_Common/Arduino.mk