Merge pull request #9 from gallib/master

Add server-to-server password support

Issue #7 partial

Check PayPal pending flag and set isPending() appropriaely.

Add test for issue #5 upp API

Remove some old Guzzle references.

Omnipay 3.x is now PSR-7 for responses and Symfony for
server requests.

Issue #4 default the errorUrl() to the returnUrl()

For card tokenisation, and authorize/purchase.

Issue #3 Support isCancelled()

Issue #3 back-port for Omnipay 2.x

No longer dev release.

Update branch alias.

Update branch alias.