Support WithBody with multiple matchers (#304)

src/WireMock.Net/Admin/Mappings/BodyModel.cs

@@ -9,5 +9,10 @@
         /// Gets or sets the matcher.
         /// </summary>
         public MatcherModel Matcher { get; set; }
+
+        /// <summary>
+        /// Gets or sets the matchers.
+        /// </summary>
+        public MatcherModel[] Matchers { get; set; }
     }
 }