Update to Node 0.10.18, bumping dev bundle version. Use caronte.
Use npm install --force to get around NPM cache corruption bug.

(This caused test_bundler_npm to fail sporadically with Node 0.8.)
Make sure all packages rebuild.

This isn't quite enough to rebuild NPM packages but it's a start.
Update run.js to use caronte API.
Use an http agent (this was default in old http-proxy but not in caronte).
Track the node version used when installing NPM modules.

This way, when the dev bundle version changes the Node version they will get
reinstalled. (You still need to bump BUILT_BY to get the modules into
unipackages too.)