This includes all internal changes from around May 20 to now.

The runtime doesn't depend on anything, so these
packages should always have been in devDependencies.

Varints are generally encoded in minimum possible length but need to
ensure that any redundancy does not break fields decoder.

"nodejs" does not exist on Travis, it appears.

These should have been included in the first match
but I overlooked them.

This involved deleting some of the code that tests
Google-internal-only features.