alexa api changes with datetime

[rjcrystal]

The alexa testing tool now sends unix timestamp as timestamp in request rather than formatted date. which causes failed to parse string exception and crashes the application.

[alexbde]

Just for people looking for a quick workaround:
Changing line 18 in Request.php from
$this->timestamp = new DateTime($data['request']['timestamp']);
to
$this->timestamp = DateTime::createFromFormat('U', $data['request']['timestamp']);
solves this issue.