Add basic implementation of VisualTest framework for osu! project.

Comes with one complimentary test.

osu.Desktop.VisualTests/Tests/TestCaseTextAwesome.cs

@@ -0,0 +1,54 @@
+using OpenTK;
+using OpenTK.Graphics;
+using osu.Framework.GameModes.Testing;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.MathUtils;
+using osu.Game.Graphics;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace osu.Desktop.Tests
+{
+    class TestCaseTextAwesome : TestCase
+    {
+        public override string Name => @"TextAwesome";
+
+        public override string Description => @"Tests display of icons";
+
+        public override void Reset()
+        {
+            base.Reset();
+
+            FlowContainer flow;
+
+            Add(flow = new FlowContainer()
+            {
+                SizeMode = InheritMode.XY,
+                Size = new Vector2(0.5f),
+                Anchor = Anchor.Centre,
+                Origin = Anchor.Centre
+            });
+
+            int i = 50;
+            foreach (FontAwesome fa in Enum.GetValues(typeof(FontAwesome)))
+            {
+                flow.Add(new TextAwesome
+                {
+                    Icon = fa,
+                    TextSize = 60,
+                    Colour = new Color4(
+                        Math.Max(0.5f, RNG.NextSingle()),
+                        Math.Max(0.5f, RNG.NextSingle()),
+                        Math.Max(0.5f, RNG.NextSingle()),
+                        1)
+                });
+
+                if (i-- == 0) break;
+            }
+        }
+    }
+}