Use chrono for struct timestamp fields

Chrono is easier to use than timestamped strings, so they should be
automatically deserialized and available for the user, instead of having
the user deserialize the strings themselves.

These fields have been changed to use a type of `DateTime<FixedOffset>`:

- `ChannelPinsUpdateEvent.last_pin_timestamp`
- `Group.last_pin_timestamp`
- `Guild.joined_at`
- `GuildChannel.last_pin_timestamp`
- `Invite.created_at`
- `Member.joined_at`
- `Message.edited_timestamp
- `Message.timestamp`
- `MessageUpdateEvent.edited_timestamp`
- `MessageUpdateEvent.timestamp`
- `PrivateChannel.last_pin_timestamp`

`Member.joined_at` is now also an `Option`. Previously, if a Guild
Member Update was received for a member not in the cache, a new Member
would be instantiated with a default String value. This is incorrect
behaviour, and has now been replaced with being set to `None` in that
case.

Id methods' `created_at()` method now return a `chrono::NaiveDateTime`
instead of a `time::Timespec`, and `User::created_at` has been updated
to reflect that.

Additionally, drop `time` as a direct dependency and use chrono for
internals.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/model/mod.rs b/src/model/mod.rs
index 26c6f42..bc414c7 100644
--- a/src/model/mod.rs
+++ b/src/model/mod.rs
@@ -40,12 +40,12 @@ pub use self::user::*;
 pub use self::voice::*;
 pub use self::webhook::*;
 
+use chrono::NaiveDateTime;
 use self::utils::*;
 use serde::de::Visitor;
 use std::collections::HashMap;
 use std::fmt::{Formatter, Result as FmtResult};
 use std::sync::{Arc, RwLock};
-use time::Timespec;
 use ::internal::prelude::*;
 
 #[cfg(feature="utils")]
@@ -63,10 +63,10 @@ macro_rules! id {
 
             impl $name {
                 /// Retrieves the time that the Id was created at.
-                pub fn created_at(&self) -> Timespec {
+                pub fn created_at(&self) -> NaiveDateTime {
                     let offset = (self.0 >> 22) / 1000;
 
-                    Timespec::new(1420070400 + offset as i64, 0)
+                    NaiveDateTime::from_timestamp(1420070400 + offset as i64, 0)
                 }
             }