problem3: solved
euler: Add initial euler template library
problem3: use euler library
problem4: initial add
euler: add palindrome function
problem4: use euler library
euler: add factors method
problem3: refactor and use euler functions
problem5: solution (232792560)

This updates euler::factors to return the prime factorization of n.
problem12: solution
problem13: add solution

./a.out < problem13.dat
problem14: solution