Add the lastlogoff fix from master to legacy Laravel4

Author: Edmandie Samonte

src/Syntax/SteamApi/Containers/Player.php

@@ -55,7 +55,7 @@ public function __construct($player)
 		$this->communityVisibilityState = $player->communityvisibilitystate;
 		$this->profileState             = $this->checkIssetField($player, 'profilestate');
 		$this->personaName              = $player->personaname;
-		$this->lastLogoff               = isset($player->lastlogoff) ? date('F jS, Y h:ia', $player->lastlogoff) : null;
+		$this->lastLogoff               = date('F jS, Y h:ia', $this->checkIssetField($player, 'lastlogoff'));
 		$this->profileUrl               = $player->profileurl;
 		$this->avatar                   = $this->getImageForAvatar($player->avatar);
 		$this->avatarMedium             = $this->getImageForAvatar($player->avatarmedium);