Added PaymentTransaction class.
Removed processingStage.
Added new query statuses system.

Now PaymentTransaction::$status indicates the status of the current payment query, 
and Payment::$status indicates the last payment request.
Callbacks now processing only processing payment transactions.
Login for settign needed action moved from PaymentProcessor to StatusQuery and AbstractFormQuery.
Refactored queries tests and folder structure.
Added PaymentTransaction::$processorType and PaymentTransaction::$processorName.
Added errors container to PaymentTransaction.
Property Payment::$clientPaymentId renamed to Payment::$clientId.
Property Payment::$paynetPaymentId renamed to Payment::$paynetId.
Property RecurrentCard::$cardReferenceId renamed to RecurrentCard::$paynetId.
Now error message for invalid email, ip or url are human-readable.
Add payment status check to ReturnQuery.
Fixed payment data updating.
Fixed queries tests.
Fixed HANDLER_PROCESSING_FINISHED handler call.
Fixed examples.
Fixed base tutorial.
Fixed documentation.