Added delete event message(#33)

* A hacky way of doing things but seems to work. Also after client restart.

example.js

@@ -127,6 +127,19 @@ client.on('message_create', (msg) => {
     }
 });
 
+client.on('message_revoke_everyone', async (after, before) => {
+    // Fired whenever a message is deleted by anyone (including you)
+    console.log(after); // message after it was deleted.
+    if (before) {
+        console.log(before); // message before it was deleted.
+    }
+});
+
+client.on('message_revoke_me', async (msg) => {
+    // Fired whenever a message is only deleted in your own view.
+    console.log(msg.body); // message before it was deleted.
+});
+
 client.on('disconnected', () => {
     console.log('Client was logged out');
 });