Authorize.net CIM Gateway: Add support for extraOptions to createCustomerProfileTransaction

This request adds 'extra options' (as defined by the Authorize.net CIM API) to the gateway implementation for creating customer profile transactions.

Their API documentation describes extra options as follows:

Information in name/value pair format that does 
not exist within CIM, such as customer IP address, etc.

The test demonstrates the effects of setting one of these extra options (by default, Authorize.net prevents duplicates within a 2 minute interval - setting 'x_duplicate_window' changes this interval) - not sure how useful that is in the context of this request though.