Transaction - Avoid dead lock

[stombre]

Explanation

Dead lock is the situation where two process lock data in a way that we can not move forward.
For example, if process 1 lock A after B, and process 2 lock B after A,
we could have a scenario where the process 1 wait for B, and the process 2 wait for A, and both lock what the other is waiting for.

Ilorm behavior

We could track in which order table / model are called, and throw exception, if we are in case we could lead to death lock.

This system, could eventually be hidden behind a flag, is used only for debugging purpose, or better; in a separate plugin.