--histogram: Add duration and power plots

  --stat

    Print mean voltage, current, and power as well as total energy consumption.

  --histogram=<n>

    Draw histogram of reported energy values per measurement interval

    (i.e., the differences between each pair of consecutive total energy readings)

    using <n> buckets.

    Draw histograms of reported energy values per measurement interval

    (i.e., the differences between each pair of consecutive total energy readings),

    measurement interval duration, and

    mean power values per measurement interval

    (calculated from energy difference and duration).

    Each histogram uses <n> buckets.

DEPENDENCIES

        plt.show()

    if "histogram" in opt:

        plt.hist((data[1:, 3] - data[:-1, 3]) * 1e-9, bins=int(opt["histogram"]))

        bin_count = int(opt["histogram"])

        plt.xlabel("Reported Energy per Measurement Interval [J]")

        plt.ylabel("Count")

        plt.hist((data[1:, 3] - data[:-1, 3]) * 1e-9, bins=bin_count)

        plt.show()

        plt.xlabel("Measurement Interval Duration [s]")

        plt.ylabel("Count")

        plt.hist((data[1:, 0] - data[:-1, 0]) * 1e-6, bins=bin_count)

        plt.show()

        plt.xlabel("Mean Power per Measurement Interval [W]")

        plt.ylabel("Count")

        plt.hist(power_from_energy, bins=bin_count)

        plt.show()