Support for nested transactions?

[haraldnh]

It looks reasonably simple to add support for begin() in a Transaction, using savepoints in postgresql. This would be useful at least in our application, and I suspect others could find it a nice addition as well.

[haraldnh]

Looking a bit more at this, it seems the best way is to merge the QueryExecutor and TransactionExecutor interfaces, i.e. any QueryExectutor supports starting a new (potentially nested) transaction. I'll make a pull request with a small proposal.