added helper function for drawing squares

include/genimg/drawing.hh

@@ -0,0 +1,10 @@
+#ifndef GENETIC_IMAGE_INCLUDE_GENIMG_DRAWING_HH_
+#define GENETIC_IMAGE_INCLUDE_GENIMG_DRAWING_HH_
+
+#include <opencv2/core/core.hpp>
+#include <opencv2/highgui/highgui.hpp>
+
+void draw_square(cv::Mat &t_img, cv::Point const &t_top_left, int const size,
+                 cv::Scalar const &t_color);
+
+#endif /* GENETIC_IMAGE_INCLUDE_GENIMG_DRAWING_HH_ */