Update the logic for ProxyAndRecord (#747)

* .

* set

* .

* .

* .

* .

* prio

* appsettings

* TinyMapperUtils

* set

* p

* nullable

* .

* ,

* fs

* .

* .

* --PreferProxyMapping

src/WireMock.Net/IMapping.cs

@@ -34,7 +34,7 @@ namespace WireMock
         string Path { get; set; }
 
         /// <summary>
-        /// Gets the priority.
+        /// Gets the priority.  (A low value means higher priority.)
         /// </summary>
         int Priority { get; }
 
@@ -91,6 +91,14 @@ namespace WireMock
         /// </value>
         bool IsAdminInterface { get; }
 
+        /// <summary>
+        /// Gets a value indicating whether this mapping is a Proxy Mapping.
+        /// </summary>
+        /// <value>
+        /// <c>true</c> if this mapping is a Proxy Mapping; otherwise, <c>false</c>.
+        /// </value>
+        bool IsProxy { get; }
+
         /// <summary>
         /// Gets a value indicating whether this mapping to be logged.
         /// </summary>