Operation (de)serialization cannot deal with numpy arrays

Defining a pulse that contains a numpy array in the data dict breaks the pulse library tests that test the (de)serialization. I suspect this is because the eval does not deal with non built-in stuff and numpy arrays are not handled seperately. Support should be extended for numpy arrays as I imagine this can be quite a common use.

For now a workaround can be to just turn it into a list.