npm shrinkwrap

We should be doing this in the stable branch to ensure fuzzy
dependencies are met identically on subsequent releases.

In this case, browserify had a change in 2.34.3 which resulted in
JSXTransformer to be a different size. While it was a change for the
better, it was unexpected and not a change we were calling out in the
release.

This shrinkwraps to the same versions of packages we had when we shipped
0.5.0.