/regions-at x y z & /nearest-place x z

/regions-at x y z [world] allows for determining regions at arbitrary
coords, a corollary to /regions-here and /regions-there

/nearest-place x z now defaults y to 64, as I do almost every time I use
the command with coords
Merge pull request #16 from mattman00000/master

/regions-at x y z & /nearest-place x z