hammer: version bump
Update elm to 0.14.

Note that elm has a different package split: The old Elm 0.13 package
is now elm-compiler, elm-make and elm-package.

Instead of invoking "elm" one now has to use "elm-make".

I kept the 0.13 version of elm around in case someone depends
on it.
Merge pull request #5481 from sjmackenzie/hammer

hammer: version bump
Merge pull request #5488 from teh/master

Update elm to 0.14.
nixpkgs: unbound 1.4.22 -> 1.5.1