This patch unifies node6 transpilation:
- instead of generating multiple top-level directories, prefixed with
`node6-`, all transpiled code gets placed under single `node6/` folder
- transpilation doesn't change require paths of transpiled modules any
more
This patch kills PhantomShim, a lightweight layer that helped to
bootstrap Puppeteer API.
At this point, PhantomShim:
- passes 139 phantomJS tests
- fails 13 tests
- lacks capabilities to run 26
The failings and unsupported tests don't have any value for Puppeteer
API, so it doesn't make sense to maintain PhantomShim any longer.
