Update CHANGES and bump version

CHANGES

@@ -1,5 +1,8 @@
+4.1.3.1 2018-12-09
+- Fix error when usersettings bypasslist is null
+
 4.1.3 2018-12-08
-- Fix sysproxy hanging issue
+- Refine sysproxy exception handling
 - Keep user bypass setting when use global proxy mode
 - Update .Net download link
 - Minor improvements

shadowsocks-csharp/Controller/Service/UpdateChecker.cs

@@ -24,7 +24,7 @@ namespace Shadowsocks.Controller
         public string LatestVersionLocalName;
         public event EventHandler CheckUpdateCompleted;
 
-        public const string Version = "4.1.3";
+        public const string Version = "4.1.3.1";
 
         private class CheckUpdateTimer : System.Timers.Timer
         {