new twin 5x5 bonus puzzles from zero
These new twin puzzles _may_ sometimes have more than one solution
I found and fixed the bug that was causing this, thanks to the alertness of sjs34
(an off-by-one bug that sometimes had an effect, only for puzzles from zero, and only
if there is at least one cage of 7 cells or larger..)
I still have to filter the existing set though, so you may still run into one of those
Edit: this has been fixed now.