Pass optional vector of boolean variables that can cause re-running the code

[jhrcook]

It could be useful to include an optional parameter that can take a vector of boolean values to cause the code to be re-run and stashed. I will need to think about whether to use any() or all() and whether to have TRUE or FALSE trigger running the code.

[torfason]

If this were to be implemented, I would argue for just a simple TRUE/FALSE value, not a vector. That way, it is up to the user to decide whether to use any() or all() if they need a more complicated setup.

Either restash or perhaps more explicitly force_restash sound like reasonable names. Other caching functions have also used rerun (I guess all of these would trigger running on TRUE, with FALSE as the default).