Update all references.  There are three remaining hits for
  git-grep '\.py\b'
all of which are scripts in "little-t-tor", not here in arti.

As per #309

Update all references.  There is one remaining hit for
  git-grep '\.sh\b'
namely "build.sh" in maint/reproducible_build, which I think is
the build script for osxcross - ie, an external project.

This is a nice reminder to have before we solve arti#303 for good.