- Pass client IP address to Paypal
- make getEndpoint() public to be consistent with other methods
- Added support for cardReference transactions and allow you to
  override previous values.  This is useful in case you want to
  do an AVS address check on a new billing billing address.

- Moved IPADDRESS parameter to getBaseData() so it is included in
  all transactions
- added getCardReference()
- added getFullMessage()
- added support for transaction void.
- If set, pass client IP on all transactions.
- Added support for cardReference transactions and allow
  override of original transaction details
- Pass transaction ID to INVNUM and put description in DESC (instead
  of using COMMENT1 variable)
- Make getEndpoint() public to be consistent with other methods
Added getCardReference()
Added support for transaction void()