The update is to get the most recent version of contextify
which is a dependency of jsdom. Previous versions of 
contextify always generate a 64 library module. v0.6.11 of
node on macos is a 32-bit ARCH. The latest version of 
contextify  builds an ARCH that matches node NOT the arch
of the system.

See: https://github.com/brianmcd/contextify/issues/19