Better handling of the end of the list of voltages

Now it runs to the end of the list, and stops when an IndexError is
thrown, when the n+1 element is tried accessed. This should work. Or so
she said, at least...
Long dataset of H1 diamond. Only to 100V

But a very loooooooong measurement at 100V. Suitable to see how long we
want to wait for the signal to stabilise.