nested transactions are working now

I found some outdated code in TransactionManager.bimage. Fixed it and everything seems to be just fine now. Scripts are now atomic.

Party time!

But its a bit too quiet here for a party. Rupali went home last night (by train, and it takes more then 24 hrs.) to help prepare for her brother's wedding the end of next month. Guess I'll just settle for a good night's sleep and a big grin.

Now if you really want to see me happy, then go and review the code and ask some questions. I don't think you will find another open source implementation of nested transactions that is as simple and easy to understand.

Now with only minor complications, I believe the code could be made to run ever so much faster, at least for the common case where transactions are not nested. But if no one is that interested in looking at the code, I see no point in making it a priority. And I see every advantage in leaving this code as simple as possible for now.

(On second thought, the speedup I was thinking of--which involves caching before images--will not work because on commit there is usually more than one block to be updated and so you need to write those before images in any case. Oh well.)

Bill