Upgrade browserify.

There are other changes I'm sure but the most important is that module
sorting results in deterministic builds.

The biggest win here comes for releases. Previously we had to jump
through hoops to make sure the files we put in bower were the same files
we put on the CDN, were the same files packaged in the Ruby gem, were
the same files we packaged into a zip file, were the same file we used
when create PRs to CDNJS. Rebuilding docs also resulted in conflicting
versions so we had to be careful when committing. This takes away all of
that pain. We can build from the same revision and get the same files.