add fitness dict parameter to class attributes and create it
add function to calculate relative probabilities of solutions to be selected
add 2 attributes to population class
write function to select 2 parents using the roulette wheel selection algorithm
return 2 solutions for 2 points crossover function (as well as mutate in place)
replace the recombine function with build_new_population
import modules modification
add function to regenerate population. this mutates population object instead of creating another
add functions to print relevant statistics
modify for testing (still missing mutation function)