Added getSingleCountryConfig() to SveaConfig, for use in i.e. tests when specifying specific merchant credentials.
Added example of how to parse the response data through SveaResponse following a hosted payment response.
SveaResponse() no longer falls back on default configuration data if no  parameter is supplied to the constructor.
Bumped version to 1.6.3, minor clarification to SveaResponse use for asynchronous payment request responses.
Merge branch 'hotfix/1.6.3'