-Fixed JValue.WriteTo losing type information with JTokenWriter

Src/Newtonsoft.Json.Tests/Linq/LinqToJsonTest.cs

@@ -55,6 +55,24 @@ namespace Newtonsoft.Json.Tests.Linq
     [TestFixture]
     public class LinqToJsonTest : TestFixtureBase
     {
+        [Test]
+        public void FromObjectGuid()
+        {
+            var token1 = new JValue(Guid.NewGuid());
+            var token2 = JToken.FromObject(token1);
+            Assert.IsTrue(JToken.DeepEquals(token1, token2));
+            Assert.AreEqual(token1.Type, token2.Type);
+        }
+
+        [Test]
+        public void FromObjectTimeSpan()
+        {
+            var token1 = new JValue(TimeSpan.FromDays(1));
+            var token2 = JToken.FromObject(token1);
+            Assert.IsTrue(JToken.DeepEquals(token1, token2));
+            Assert.AreEqual(token1.Type, token2.Type);
+        }
+
         [Test]
         public void ToObject_Guid()
         {

Src/Newtonsoft.Json/Linq/JValue.cs

@@ -819,11 +819,13 @@ namespace Newtonsoft.Json.Linq
                     writer.WriteValue((byte[])_value);
                     return;
                 case JTokenType.Guid:
+                    writer.WriteValue((_value != null) ? (Guid?)_value : null);
+                    return;
                 case JTokenType.TimeSpan:
-                    writer.WriteValue((_value != null) ? _value.ToString() : null);
+                    writer.WriteValue((_value != null) ? (TimeSpan?)_value : null);
                     return;
                 case JTokenType.Uri:
-                    writer.WriteValue((_value != null) ? ((Uri)_value).OriginalString : null);
+                    writer.WriteValue((Uri)_value);
                     return;
             }