Moves XNA 4 files for Github migration.

Plan B Html Parser/Tokens/HtmlBeginSpanToken.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace PlanB.Html.Tokens
+{
+    internal class HtmlBeginSpanToken: HtmlToken
+    {
+        public override string ToString()
+        {
+            return "<span>";
+        }
+    }
+}