Merge pull request #7 from zot24/master

Explained how to load the plugin on bootstrap.php
Slight change to grammar/wording
adds NOTIFYURL to SetExpressCheckout
Test that PAYMENTREQUEST_0_NOTIFYURL is set
Merge pull request #10 from timstermatic/master

adds NOTIFYURL to SetExpressCheckout
Includes test case update. Merge branch 'master' of github.com:robmcvey/cakephp-paypal