Handle URI parameter errors returned by the API

ParamError.cs

@@ -0,0 +1,22 @@
+
+namespace HabitSharp {
+    /// <summary>
+    /// Describes a Habitica request parameter error.
+    /// </summary>
+    public class ParamError {
+        /// <summary>
+        /// The problematic URI parameter name.
+        /// </summary>
+        public string Param { get; set; }
+        
+        /// <summary>
+        /// The given parameter value.
+        /// </summary>
+        public string Value { get; set; }
+
+        /// <summary>
+        /// A message describing the nature of the parameter error.
+        /// </summary>
+        public string Message { get; set; }
+    }
+}

Result.cs

@@ -1,10 +1,21 @@
 using System.Collections.Generic;
+using RestSharp.Deserializers;
 
 namespace HabitSharp {
     public class Result<T> {
         public bool Success { get; set; }
+
         public T Data { get; set; }
+
         public List<Notification> Notifications { get; set; }
+
+        public string Error { get; set; }
+
+        [DeserializeAs(Name="message")]
+        public string ErrorMessage { get; set; }
+
+        [DeserializeAs(Name="errors")]
+        public List<ParamError> ParamErrors { get; set; }
     }
 
     public class ListResult<T> : Result<List<T>> { }