add code_size() to Program class
add code_size() to Program class

Fixes #125 in a generic way

Kattis/problemtools,Kattis/problemtools,ghamerly/problemtools,jsannemo/problemtools,jsannemo/problemtools,ghamerly/problemtools,ghamerly/problemtools,ghamerly/problemtools,Kattis/problemtools,jsannemo/problemtools,jsannemo/problemtools,Kattis/problemtools