Revert "Add code blocks as a single history entry."

We'll bring it back, because it's a good idea, but the current
implementation doesn't play nice with codecleaners... We're a bit at
odds because we need to add the raw code block to the history, but
execute the cleaned code block.

This reverts commit e6bd6b306f5e6c86725b9084c61baaa0120a1a15.
Add code blocks as a single history entry.

This has the awesome side effect of hoisting commands used inside code block declarations so that the code block can be replayed more effectively.

This way done right :P

(Effectively re-reverting 535444c)