Journal changes accross multiple transactions. Push/Pop transaction

[rakita]

Journaling changes across multiple transactions can be very beneficial as transaction with a Journal can be reverted.

• Need to handle hot/cold marker of account (Idea make a bool flag a u32, and increment global marker N by one when new tx starts, so N would make it warm while < N would make it cold).
• Remove some cleanup in PostExecution handler.
• Add an interface that would push and pop transactions.
• Handle error state and recovery after it. Should we revert all changes automatically or leave for the caller to do it?
• Add close block function so the output of multiple transaction executions can be delivered.