Introduce concept of HitObjectParsers, fix tests and stop using reflection (unreliable due to lazy loading).

osu.Game.Mode.Osu/Objects/OsuHitObjectParser.cs

@@ -0,0 +1,45 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using osu.Game.Beatmaps.Samples;
+using osu.Game.Modes.Objects;
+using OpenTK;
+
+namespace osu.Game.Modes.Osu.Objects
+{
+    public class OsuHitObjectParser : HitObjectParser
+    {
+        public override HitObject Parse(string text)
+        {
+            string[] split = text.Split(',');
+            var type = (OsuBaseHit.HitObjectType)int.Parse(split[3]);
+            bool combo = type.HasFlag(OsuBaseHit.HitObjectType.NewCombo);
+            type &= (OsuBaseHit.HitObjectType)0xF;
+            type &= ~OsuBaseHit.HitObjectType.NewCombo;
+            OsuBaseHit result;
+            switch (type)
+            {
+                case OsuBaseHit.HitObjectType.Circle:
+                    result = new Circle();
+                    break;
+                case OsuBaseHit.HitObjectType.Slider:
+                    result = new Slider();
+                    break;
+                case OsuBaseHit.HitObjectType.Spinner:
+                    result = new Spinner();
+                    break;
+                default:
+                    //throw new InvalidOperationException($@"Unknown hit object type {type}");
+                    return null;
+            }
+            result.Position = new Vector2(int.Parse(split[0]), int.Parse(split[1]));
+            result.StartTime = double.Parse(split[2]);
+            result.Sample = new HitSampleInfo { Type = (SampleType)int.Parse(split[4]) };
+            result.NewCombo = combo;
+            // TODO: "addition" field
+            return result;
+        }
+    }
+}