Support deserializing from bincode

Bincode is a minimal format that expects the Deserialize
implementation to tell it what type of data it should
expect to see.

src/datetime.rs

@@ -496,7 +496,7 @@ mod serde {
         fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
             where D: de::Deserializer
         {
-            deserializer.deserialize(DateTimeVisitor)
+            deserializer.deserialize_str(DateTimeVisitor)
         }
     }
 
@@ -504,7 +504,7 @@ mod serde {
         fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
             where D: de::Deserializer
         {
-            deserializer.deserialize(DateTimeVisitor).map(|dt| dt.with_timezone(&UTC))
+            deserializer.deserialize_str(DateTimeVisitor).map(|dt| dt.with_timezone(&UTC))
         }
     }
 
@@ -512,7 +512,7 @@ mod serde {
         fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
             where D: de::Deserializer
         {
-            deserializer.deserialize(DateTimeVisitor).map(|dt| dt.with_timezone(&Local))
+            deserializer.deserialize_str(DateTimeVisitor).map(|dt| dt.with_timezone(&Local))
         }
     }
 

src/naive/date.rs

@@ -1581,7 +1581,7 @@ mod serde {
         fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
             where D: de::Deserializer
         {
-            deserializer.deserialize(NaiveDateVisitor)
+            deserializer.deserialize_str(NaiveDateVisitor)
         }
     }
 

src/naive/datetime.rs

@@ -1143,7 +1143,7 @@ mod serde {
         fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
             where D: de::Deserializer
         {
-            deserializer.deserialize(NaiveDateTimeVisitor)
+            deserializer.deserialize_str(NaiveDateTimeVisitor)
         }
     }
 

src/naive/time.rs

@@ -1268,7 +1268,7 @@ mod serde {
         fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
             where D: de::Deserializer
         {
-            deserializer.deserialize(NaiveTimeVisitor)
+            deserializer.deserialize_str(NaiveTimeVisitor)
         }
     }