plot_image.py: use modern print() syntax everywhere
-rw-r--r-- 9 .gitignore
-rw-r--r-- 630 .htaccess
drwxr-xr-x - _doc
drwxr-xr-x - _script
drwxr-xr-x - assignments
drwxr-xr-x - content
drwxr-xr-x - grades
-rw-r--r-- 862 index.shtml
drwxr-xr-x - lectures_and_recitations
drwxr-xr-x - objectives
drwxr-xr-x - resources
drwxr-xr-x - shared
drwxr-xr-x - src