2013: save a character in problem 6

save some brackets in 2021 prob 7 solution

Minor improvements to 2014 solutions

Add a couple of minor cosmetic improvements

finish up last of the 2021 problems

add more solutions for 2021

save a whole character in 2017.prob6!

use •Repr instead of •Fmt for formatting numbers

more work on 2020 problems

solve one and a half more problems from 2020

Add more solutions for 2020

add remaining solutions for 2019

Create util.bqn and import it where used
Also shorten somewhat the definition of `letters`.

fix errors in 2018 problems 8 and 9

finish off 2018 and do a little golfing

add some solutions for 2018