Support to Omnipay v3

Support to omnipay version 3 (#8)

* Update to omnipay 3

- Update to omnipay 3 is necessary to be able to work with laravel 5.6

Signed-off-by: Andres Garcia <andresgarcia@gmail.com>

* Update Readme

Signed-off-by: Andres Garcia <andresgarcia@gmail.com>

* Change createRequest for request method

Signed-off-by: Andres Garcia <andresgarcia@gmail.com>

* Rewind stream to avoid null messages

Signed-off-by: Andres Garcia <andresgarcia@gmail.com>

* Update composer json and fix EOL

Signed-off-by: Andres Garcia <andresgarcia@gmail.com>

Responses with FailureData but 2xx response code are declined

Responses with FailureData but 2xx response code are declined (#7)

* A 201 http response with FailureData is a unsuccessful transaction

- An example would be an “Account ABA number is invalid.” when try to process a payment.

Signed-off-by: Andres Garcia <andresgarcia@gmail.com>

* Break long IF in multiple lines

Signed-off-by: Andres Garcia <andresgarcia@gmail.com>

* Fix end of lines spaces

Signed-off-by: Andres Garcia <andresgarcia@gmail.com>

List / Delete CreditCard / ACH Accounts

Add 4 new methods:

• retrieveBankAccounts
• retrieveCreditCards
• deleteCreditCard
• deleteBankAccount

Retrieve Payment method

Add retrieve payment method

Fix documentation

Merge pull request #2 from dranes/dev-1.0.1

Fix version mismatch on readme

Initial Release basic omnipay features

• include Create BankAccount, CreditCard, purchase, refund and void.