Added "validate-digits" to "system.xml" in order to do minimum client side validation.
Merge pull request #80 from itnova/develop-2.1.1

Stick to naming conventions to enable use of $event->getAdyenResponse();
Change readme text
Merge remote-tracking branch 'origin/develop-2.1.1' into develop-2.1.1
Merge pull request #82 from Lanenga/develop-2.1.1

Added minimum client side validation on "delivery_days".
Fixes #83 clean code and reactivate the quote after canceling on HPP
Merge remote-tracking branch 'origin/develop-2.1.1' into develop-2.1.1
[develop-2.1.1] +: Add adyen_event collection model to be able to query collections instead of querying the DB directly