Removing the old exception classes.
Adding Hps.php to include new exception classes and make the sdk more like the others
Updating the hpsChargeService to use the new Hps.php file
Removing require because it is now covered by Hps.php
Should have been using map_issuer instead of map_gateway
Fixing a couple of bugs created when switching to the new ExceptionMapper
Fixing the List response
Merge pull request #11 from bertoncobb/full_error_handling

Full error handling