It is now possible to parse parts of the program and save the IR for
later addition. This is currently used for while loops but will also make other
control flow elements easier to implement in the future.
So basically, I used i++ on a linked list instead of i->next. As if that
wasn't bad enough on its own, it even managed to somehow still work in the 2
test scenarios I gave it. Regardless, it is now fixed.
The unification of memory pools also fixed some memory leaks and
hopefully reduced the mallocs of identifier strings significantly by
giving them the same pool as the token stream.
