Added support for custom params and access token usage in card reader requests

These are both optional features, the api should be able to add custom params and/or access token, and also not use it at all.

If custom params are used in request builder (present), they are added to the query string. Supports only a String/String map to force clients to place string equivalent values into the map. (Leaves majority of 'issues'' on their side and not the library side with adding crazy custom params). Expecting mostly string or number values here anyways.

Access token is added to query string if present.