Add Transaction.terminate() to the Transaction API

This allows the user to terminate a transaction, which is a more
forceful mode of failure that not only marks the transaction as failed
(i.e. such that it will be rolled back) but also causes any subsequent
kernel operations contained within that transaction to throw
an exception.

This functionality will be used as a user-facing query termination
facility.

Signed-off-by: Stefan Plantikow <stefan.plantikow@neotechnology.com>
Add support for interrupting transactions in the shell with Ctrl+C

Signed-off-by: Stefan Plantikow <stefan.plantikow@neotechnology.com>
Adding tutorial for interrupting transactions to advanced section of manual

Use FileUtils.deleteRecursively() instead of copy-and-pasting similar code in all tutorials

Signed-off-by: Andres Taylor <andres.taylor@neotechnology.com>
Address review comments
Merge pull request #2654 from jakub-/transaction-terminate

Add Transaction.terminate() to the Transaction API