User sessions should be in Isabelle syntax

[Twigonometry]

Currently, user sessions are written in Haskell. This causes a few issues:

• they must be reformatted to isabelle for users to manually test them (in the theory file)
• requires extra knowledge of haskell, beyond just isabelle
• requires knowing which types from the exported haskell code to use to get correct format (e.g. Int_of_integer). This can be confusing, as export_code can create strange functions and wrappers, and cannot be known in advance

Instead, we should create some intermediary function that translates isabelle user sessions to haskell, so that we can still run the auto_test cases

[Twigonometry]

Use a function like the following to harvest the translated user sessions and then output them to another file, so they can be used if --auto_test is specified:

definition test :: "int session" where mytest [code] :
"test = Items (Pop (Pop (Push 4 (Pop (Push 3 (Push 2 (Push (1::int) (Init [] []))))))))"