Correct the logic

Correct the cancelled

Use order ID

PHPCS

Throw exception when cannot get access token

compatibility omnipay v3

Added strict return type of string for TransactionId and TransactionR…

…eference

Merge pull request bileto#5 from bileto/fix-transation-id

Fixed TransactionId and TransactionReference to refer for right meaning

Merge pull request bileto#4 from bileto/better-understanding-of-state

Fix for smarter handling of status changes

Merge pull request bileto#2 from bileto/accept-notifications

Accept notifications from PayU