Copter: add Circle parameter

ArduCopter/Parameters.h

@@ -140,6 +140,7 @@ public:
         k_param_wp_nav,
         k_param_attitude_control,
         k_param_pos_control,
+        k_param_circle_nav,     // 104
 
         // 110: Telemetry control
         //

ArduCopter/Parameters.pde

@@ -1007,6 +1007,10 @@ const AP_Param::Info var_info[] PROGMEM = {
     // @Path: ../libraries/AC_WPNav/AC_WPNav.cpp
     GOBJECT(wp_nav, "WPNAV_",       AC_WPNav),
 
+    // @Group: WPNAV_
+    // @Path: ../libraries/AC_WPNav/AC_Circle.cpp
+    GOBJECT(circle_nav, "CIRCLE_",  AC_Circle),
+
     // @Group: ATCON_
     // @Path: ../libraries/AC_AttitudeControl/AC_AttitudeControl.cpp
     GOBJECT(attitude_control, "ATTCON_", AC_AttitudeControl),