Merge new `stack`-like function with `stack`?

[light-matters]

In addressing #67 and the desire to reduce duplication in compositions like prepare_atoms, i.e. killing the need to make intermediary kws and functions, we now have cascade:

def cascade(*fs, **kws):
    """
    Similarly to `stack`, a convenience that combines an arbitrary chain of functions with an arbitrary selection of associated keywords.

    Currently, `kws` are passed to the associated functions by prefixing, e.g. `cascade(MOT, molasses,  MOT_duration=1.0)` creates a `stack` of `MOT` and `molasses`, with `duration=1.0` passed into the `MOT` function before evaluation.

    The motivation for this feature is that different experimental contexts should be built modularly, but, at final composition, the user often just wants a single point of contact to add/change nested variables.
    """

It is similar enough to stack that it might be possible to combine the two, but we should consider the pros and cons, e.g. would it be too confusing for the user? Basically it could work as an extension, where kws that match the pattern for cascade could be cascaded and those that don't could just be added to every function.