Removed spaces from top-level directory names.

Spaces tend to cause annoyances in a Unix-style shell environment.
This change fixes that.

61_Math_Dice/csharp/StringExtensions.cs

@@ -0,0 +1,15 @@
+namespace MathDice
+{
+    public static class StringExtensions
+    {
+        private const int ConsoleWidth = 120; // default console width
+
+        public static string CentreAlign(this string value)
+        {
+            int spaces = ConsoleWidth - value.Length;
+            int leftPadding = spaces / 2 + value.Length;
+
+            return value.PadLeft(leftPadding).PadRight(ConsoleWidth);
+        }
+    }
+}