Updating username added

I was wrong about the username not needing to be set by the result from
Snapchat, sorry.

Author: Jeffrey

src/snapchat.php

@@ -105,8 +105,9 @@ public function login($username, $password) {
       )
     );
 
-    // If 'logged' is true (aka successful login), set the auth_token
+    // If 'logged' is true (aka successful login), set the username and auth_token
     if ($result->logged) {
+      $this->username = $result->username;
       $this->auth_token = $result->auth_token;
     }
 
@@ -1177,4 +1178,4 @@ public function updateEmail($email) {
     return isset($result->param) && $result->param == $email;
   }
 
-}
+}