Implementation of the Last Index of Zero problem.

This is my stab at implementing the Last Index of Zero problem from iJava, where the goal is to take a list of integers containing at least one zero, and return the zero-based index of the last zero in the list.

Most of this was based on a previous problem from thelmuth. The most "creative" part was creating the test suite, which he should definitely look over before pulling this in and using it.
thelmuth/instruction-additions
Made my domains vectors, and improved length distribution of random inputs.

I was generating lists instead of vectors for several of my test domains, which apparently breaks the world, and could certainly have contributed to my poor results when I did a few runs on this problem. I also improved the length distribution of randomly generated inputs so there hopefully isn't so much reward for generating a constant that is the roughly half the length of the most dominant input vector length.
Forgot to map vec over result of permutations.

In my previous fix I'd applied vec to the result of permutations, which turned the *outer* list to a vector, but didn't change any of the contained collections, all of which remained lists. Mapping vec across the result fixes that.
Started Count Odds problem
Merge remote-tracking branch 'nmcphee/last-index-of-zero' into prog-synth-benchmarks
Merge branch 'master' into prog-synth-benchmarks