complete refactor

Blueberry.Redmine/RedmineApiException.cs

@@ -0,0 +1,17 @@
+namespace Blueberry.Redmine
+{
+    public class RedmineApiException : Exception
+    {
+        public int? StatusCode { get; }
+
+        public RedmineApiException(string message, int? statusCode = null) : base(message)
+        {
+            StatusCode = statusCode;
+        }
+
+        public RedmineApiException(string message, Exception innerException, int? statusCode = null) : base(message, innerException)
+        {
+            StatusCode = statusCode;
+        }
+    }
+}