Misc (#19)

* get image returns optional<Mat> instead of unique_ptr<Mat>

* introduce complexity

* rename image load function

* add example for a basic reader for binary image files

* fix windows build?

* add a status bar underneath the menu bar

* use status bar in custom_0 example app

* clang formats

* packing w/ pragma push

* add "Save As" functions to image views

* resize over reserve

* rm local override uri

* add simple thread pool

* rename to simple_thread_pool

* get rid of useless renderlib

* document version inc

* extract hardcoded values to in-header

* clang format patch

* clone registered image in custom_0

* document binary-file header

* minor fixes

* clang format

* rm unused render cmake

lib/imaging/IPixelariumImage.cpp

@@ -0,0 +1,15 @@
+#include "IPixelariumImage.hpp"
+
+#include <opencv2/imgcodecs.hpp>
+
+bool pixelarium::imaging::IPixelariumImageCvMat::SaveImage(const std::string& uri)
+{
+    auto current_image = this->TryGetImage();
+
+    if (!current_image.has_value())
+    {
+        return false;
+    }
+
+    return cv::imwrite(uri, current_image.value());
+}