Fixing modules for switching
This commit contains the following major changes
- Fixing the Module (Π) for switching
- Adding the necessary definitions/lemmas to the linking module, abstracting over the environment using ghost variables
- Add a PoC proof of a recursive rec program linking with a spec program
- Some new Notations
- Rework of the memmove example -> Motivates a more general treating of external calls (Wip)
- Auxiliary lemmas