re-added grid-rendering to the editor

rebuild grid/navMesh 3D data only if needed

mapview/3D/misc/TriangleData.h

@@ -59,6 +59,17 @@ public:
 
 	}
 
+	void addPoint(Point3 p, const float r, const float g, const float b, const float a) {
+
+		vertices.insert(vertices.end(), {p.x, p.y, p.z});
+		rgba.insert(rgba.end(), {r,g,b,a});
+
+	}
+
+	bool empty() const {
+		return vertices.empty();
+	}
+
 	void clear() {
 		vertices.clear();
 		normals.clear();