Change global widget container to page

src/gui/Page.cpp

@@ -0,0 +1,22 @@
+#include "../../include/gui/Page.hpp"
+#include "../../include/gui/Widget.hpp"
+
+namespace gsr {
+    void Page::add_widget(std::unique_ptr<Widget> widget) {
+        widgets.push_back(std::move(widget));
+    }
+
+    void Page::on_event(mgl::Event &event, mgl::Window &window) {
+        // Process widgets by visibility (backwards)
+        for(auto it = widgets.rbegin(), end = widgets.rend(); it != end; ++it) {
+            if(!(*it)->on_event(event, window))
+                return;
+        }
+    }
+
+    void Page::draw(mgl::Window &window) {
+        for(auto &widget : widgets) {
+            widget->draw(window);
+        }
+    }
+}