Have the macro repository working, just need to write more unit tests regarding macro properties.

src/Umbraco.Core/Models/MacroPropertyCollection.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Collections.ObjectModel;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Umbraco.Core.Models
+{
+    /// <summary>
+    /// A macro's property collection
+    /// </summary>
+    internal class MacroPropertyCollection : ObservableDictionary<string, IMacroProperty>
+    {
+        public MacroPropertyCollection() 
+            : base(property => property.Alias)
+        {
+        }
+
+    }
+
+}