added "content_available" flag for iOS compatibility

library/CodeMonkeysRu/GCM/Message.php

@@ -85,6 +85,17 @@ class Message
      */
     private $restrictedPackageName = null;
 
+    /**
+     * On iOS, use this field to represent content-available in the APNS payload. When a
+     * notification or message is sent and this is set to true, an inactive client app is
+     * awoken. On Android, data messages wake the app by default.
+     *
+     * Optional.
+     *
+     * @var bool
+     */
+    private $contentAvailable = true;
+
     /**
      * Allows developers to test their request without actually sending a message.
      *
@@ -201,4 +212,14 @@ public function setDryRun($dryRun)
         return $this;
     }
 
+    public function getContentAvailable()
+    {
+        return $this->contentAvailable;
+    }
+
+    public function setContentAvailable($contentAvailable)
+    {
+        $this->contentAvailable = $contentAvailable;
+        return $this;
+    }
 }

library/CodeMonkeysRu/GCM/Sender.php

@@ -152,6 +152,7 @@ private function formMessageData(Message $message)
             'time_to_live' => 'getTtl',
             'restricted_package_name' => 'getRestrictedPackageName',
             'dry_run' => 'getDryRun',
+            'content_available' => 'getContentAvailable',
         );
 
         foreach ($dataFields as $fieldName => $getter) {