Stef negate matcher (#134)

* RejectOnMatch (wip)

* RejectOnMatch (wip)

* RejectOnMatch (wip)

* RejectOnMatch (wip)

* docs: improve sample app matcher to show use of reject on match

* Reworked code review comments

src/WireMock.Net/Matchers/MatchBehaviourHelper.cs

@@ -0,0 +1,28 @@
+
+namespace WireMock.Matchers
+{
+    internal static class MatchBehaviourHelper
+    {
+        /// <summary>
+        /// Converts the specified match behaviour and match value to a new match value.
+        /// 
+        /// if AcceptOnMatch --> return match (default)
+        /// if RejectOnMatch and match = 0.0 --> return 1.0
+        /// if RejectOnMatch and match = 0.? --> return 0.0
+        /// if RejectOnMatch and match = 1.0 --> return 0.0
+        /// </summary>
+        /// 
+        /// <param name="matchBehaviour">The match behaviour.</param>
+        /// <param name="match">The match.</param>
+        /// <returns>match value</returns>
+        internal static double Convert(MatchBehaviour matchBehaviour, double match)
+        {
+            if (matchBehaviour == MatchBehaviour.AcceptOnMatch)
+            {
+                return match;
+            }
+
+            return match <= MatchScores.Tolerance ? MatchScores.Perfect : MatchScores.Mismatch;
+        }
+    }
+}