Initial commit of existing code.

* All renderdoc code up to this point was written by me, history is available by request

WinFormsUI/Docking/FloatWindowCollection.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Drawing;
+using System.Windows.Forms;
+
+namespace WeifenLuo.WinFormsUI.Docking
+{
+    public class FloatWindowCollection : ReadOnlyCollection<FloatWindow>
+    {
+        internal FloatWindowCollection()
+            : base(new List<FloatWindow>())
+        {
+        }
+
+        internal int Add(FloatWindow fw)
+        {
+            if (Items.Contains(fw))
+                return Items.IndexOf(fw);
+
+            Items.Add(fw);
+            return Count - 1;
+        }
+
+        internal void Dispose()
+        {
+            for (int i=Count - 1; i>=0; i--)
+                this[i].Close();
+        }
+
+        internal void Remove(FloatWindow fw)
+        {
+            Items.Remove(fw);
+        }
+
+        internal void BringWindowToFront(FloatWindow fw)
+        {
+            Items.Remove(fw);
+            Items.Add(fw);
+        }
+    }
+}