118 transaction support

Here it is, the big one. Transaction support. I honestly don't really expect anyone to code review this monstrosity, but you may as well. Bundled with this branch:

* :blowfish: Transactions
* Test scrip improvements
* Random bugfixes I found and fixed
* :star2: Huge speed regressions! :star2:
* Durability
why `'\0'` and not `0`