Add solutions to the problems 1-8
Update the README
Add a solution to the 9th problem
Add a solution to the 10th problem
Add solution to the 11th problem
Improve formatting; add some comments
Add the answer
Add solutions to problems 12-13
Add solution to the 14th problem
Add solution to the 15th problem
Add the answer
Reorganize solutions into directories; add the overview PDFs
Add a C solution to the problem 15
Move the is_prime function to a separate module
Loop through odd numbers only
Add .gitignore
Add a function implementing the Sieve of Eratosthenes to the module; import it in solutions 5 and 10
Refactor to use the number-of-divisors function
Improve formatting
Add a solution to problem 16