Hi,

I have committed fixes to transaction isolation level code.

- TRANSACTION_NONE throws exception;

- TRANSACTION_READ_UNCOMMITTED is promoted to TRANSACTION_READ_COMMITTED;

- setTransactionIsolation(int) commits current transaction (if this
cases many problems in your code I can delay setting new isolation
level until next start, but this requires more work);

- setAutoCommit(boolean) never starts transaction on its own;

- commit()/rollback() do not start transaction on their own;

Best regards,
Roman Rokytskyy