Core pr 5

Coding style and add support for extra parameters to CURL to support proxies.
Is `curl_options` a variable which is used elsewhere? I have not seen references to it elsewhere. If not then it should be prefixed with `ting_client` or the like.

In general I would prefer to keep as much of the Drupal API out of this as possible. The constructor already supports passing options. Why not include `curl_options` as a part of these and set it as a protected property for the class?