Adding new follow target navigation and main states. New follow target

topic added. New follow fsm added to the navigator

src/modules/navigator/follow_target.h

@@ -0,0 +1,65 @@
+/***************************************************************************
+ *
+ *   Copyright (c) 2016 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+/**
+ * @file followme.cpp
+ *
+ * Helper class to track and follow a given position
+ *
+ * @author Jimmy Johnson <catch22@fastmail.net>
+ */
+
+#pragma once
+
+#include <controllib/blocks.hpp>
+#include <controllib/block/BlockParam.hpp>
+
+#include "navigator_mode.h"
+#include "mission_block.h"
+
+class FollowTarget : public MissionBlock
+{
+	Navigator *_navigator;
+	int		_tracker_motion_position_sub;	/**< tracker motion subscription */
+
+public:
+    FollowTarget(Navigator *navigator, const char *name);
+
+    ~FollowTarget();
+
+    virtual void on_inactive();
+
+    virtual void on_activation();
+
+    virtual void on_active();
+
+};