[SharpDX] Fix bug so that MathUtil.NextLong can produce the specified…

… max value

Previously, the largest value it could ever return was max - 1.

This also eliminates a divide by zero issue that happened when when max == min.

Source/SharpDX/MathUtil.cs

@@ -481,7 +481,7 @@ public static long NextLong(this Random random, long min, long max)
             random.NextBytes(buf);
             long longRand = BitConverter.ToInt64(buf, 0);
 
-            return (Math.Abs(longRand % (max - min)) + min);
+            return (Math.Abs(longRand % (max - min + 1)) + min);
         }
 
         /// <summary>
@@ -654,7 +654,7 @@ public static long NextLong(Random random, long min, long max)
             random.NextBytes(buf);
             long longRand = BitConverter.ToInt64(buf, 0);
 
-            return (Math.Abs(longRand % (max - min)) + min);
+            return (Math.Abs(longRand % (max - min + 1)) + min);
         }
 
         /// <summary>