rework option handling
It's desirable at times to know whether or not a user has set an option in the .mod file.
To do this, we can hack the preprocessor to maintain a separate cellarray, that it would assign to every time it encounters an option. Something to the effect of:
'option' , assigned , default_val <>, <<0 or 1>>, <>
This can be done in the preprocessor without changing the backend matlab code. It would thereby provide the possibility, when needed, to check whether or not an option was assigned by the user, allowing us to know whether or not we can change the value.