[OSAB] Task 5: Render histogram statistics box using box_text

[robert]

This is one way to solve Task 5 in https://robertheaton.com/2019/04/14/open-source-for-advanced-beginners-1-bashplotlib/ .

Test

I ran:

from bashplotlib.histogram import plot_hist

plot_hist('scratch_data.txt', showSummary=True)

and got the output:

------------------------------
|       ## Summary ##        |
|      observations: 12      |
|      mean : 4.583333       |
|     std dev : 2.503028     |
|    max value: 7.000000     |
|    min value: 1.000000     |
------------------------------