Issue with payload size on a GET

[jsgoecke]

It was reported that this was added/replaced:

curl_setopt($this->ch, CURLOPT_HTTPHEADER, array());

On or about line 287:

https://github.com/tropo/tropo-webapi-php/blob/master/tropo-rest.class.php#L287

A pull request would be great, but detailing exactly what would was done would suffice.