added interface for walkers

some new helper methods
added interpolater for paths

floorplan/Floor.h

@@ -24,6 +24,9 @@ private:
 
 public:
 
+	/** empty ctor */
+	Floor() {;}
+
 	/** ctor */
 	Floor(const float width_cm, const float depth_cm) : width_cm(width_cm), depth_cm(depth_cm) {;}