VisualBuilder: Start working on an interface builder application.

It's tedious making interfaces programmatically. Let's make a program to
help us with this. :^)

Applications/VisualBuilder/VBForm.cpp

@@ -0,0 +1,25 @@
+#include "VBForm.h"
+#include <LibGUI/GPainter.h>
+
+VBForm::VBForm(const String& name, GWidget* parent)
+    : GWidget(parent)
+{
+    set_fill_with_background_color(true);
+    set_background_color(Color::LightGray);
+}
+
+VBForm::~VBForm()
+{
+}
+
+void VBForm::paint_event(GPaintEvent& event)
+{
+    GPainter painter(*this);
+    painter.add_clip_rect(event.rect());
+
+    for (int y = 0; y < height(); y += m_grid_size) {
+        for (int x = 0; x < width(); x += m_grid_size) {
+            painter.set_pixel({ x, y }, Color::Black);
+        }
+    }
+}