make as python package

[p208p2002]

i'v change it into a python package so we can install via github like this

$ pip install -U git+https://github.com/p208p2002/pretty-print-confusion-matrix

and usage

from pretty_cm import plot_confusion_matrix_from_data, pretty_plot_confusion_matrix

also add new arg save_name for plot_confusion_matrix_from_data and pretty_plot_confusion_matrix
this arg allow user save plt as image