Options for cUrl adapter

[akDeveloper]

Options do not merge correctly when re-using cUrl adapter for concurrent requests.

https://github.com/akDeveloper/Aktive-Merchant/blob/master/lib/AktiveMerchant/Http/Adapter/cUrl.php#L231

Array in $default variable holds the new data including the new url and should replace any data in $this->options array.

A temporary workaround is to overwrite the getAdapter method in a Gateway class and always return a new instance of cUrl adapter.