added marr.datamapper source code for easy debugging.

Marr.Data/ExtensionMethods.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Data.Common;
+
+namespace Marr.Data
+{
+    /// <summary>
+    /// This class contains public extension methods.
+    /// </summary>
+    public static class ExtensionMethods
+    {
+        /// <summary>
+        /// Gets a value from a DbDataReader by using the column name;
+        /// </summary>
+        public static T GetValue<T>(this DbDataReader reader, string columnName)
+        {
+            int ordinal = reader.GetOrdinal(columnName);
+            return (T)reader.GetValue(ordinal);
+        }
+    }
+}