In hidapi v0.4.1 it is not yet possible to store the HidDevice in a
struct. Although there is already a pull request to implement this, it is not yet merged.
The read function is now moved into the Pedals object and split up to
read_pedals() (which reads all pedals and prints the output) and
read_pedal() (which only reads one pedal).
Furthermore, the beginning of write_pedal() and write_pedals() is added.
