Merge pull request #14 from kowalgta/master

No currency required with DataCash
Merge pull request #15 from kowalgta/master

Reverted change to DataCashRequestBuilderBase and removed Currency from RefundTransactionRequestBuilder!
Merge pull request #16 from kowalgta/master

Changes to DataCash refunds
Merge pull request #17 from kowalgta/master

Refund functionality is exposed as a separate gateways
Merge pull request #18 from kowalgta/master

Need to expose IRefundGateway functionality to be more functional :-)
Merge pull request #19 from kowalgta/master

After reality check with PayPal I came out with something like this
Merge pull request #21 from kowalgta/master

PayPal API...
Accept billing address in payments (issue #22)
Return AVSCV2 result in response (issue #22)
Postcodes 9 alphanumeric characters (issue #23)
Only pass numeric address (issue #24)
Guard against empty postcode (issue #24)
PayPal recurring payments.

Fixed decimal format when converting to string, by using invariant
culture parameter.
Merge pull request #26 from kowalgta/master

MassPay functionality
Corrected numbering of recurrent payments for PayPal.
Added InvariantCulture to number formating.

Added PayPal Recurring Payments feature to README.md file.
Added integration test for paypal recurring profiles.
New integration tets for recurring profiles.
Merge recurring payments
Subject attributes required for running tests