Integration of the path planner into rtabmap's memory management to actually retrieve nodes on the planned path on the graph.

Added Rtabmap::clearPath(), Rtabmap::computePath(), Rtabmap::getPathGoalId() and Rtabmap::updateGoalIndex() methods.
Added virtual links when path retrieval is activated (virtual links are not saved to database and removed when the path goal is reached).
New parameters: RGBD/GoalReachedRadius and RGBD/MaxAnticipatedNodes
Refactored how loop closure hypotheses are selected (fixed ratio between consecutive hypotheses, not the last loop closure).
Updated getNodesInRadius() to use all filtered scans.
GUI: window can be saved/loaded maximized
GUI: saving Graph View parameters to config.ini

guilib/include/rtabmap/gui/MainWindow.h

@@ -102,6 +102,7 @@ public:
 
 	QString getWorkingDirectory() const;
 	void setMonitoringState(bool pauseChecked = false); // in monitoring state, only some actions are enabled
+	bool isSavedMaximized() const {return _savedMaximized;}
 
 public slots:
 	void processStats(const rtabmap::Statistics & stat);
@@ -266,6 +267,7 @@ private:
 	bool _emptyNewDatabase;
 	bool _odomImageShow;
 	bool _odomImageDepthShow;
+	bool _savedMaximized;
 
 	QMap<int, Signature> _cachedSignatures;
 	std::map<int, Transform> _currentPosesMap; // <nodeId, pose>