Fix the node_modules path for the nodejs runner
Remove double definition
Add pwd to nodejs/dir and extract __glob__
Extract __fs__ and __path__ in nodejs/file
Support runtime requires in Nodejs
Update the mspec signature in bin/opal-mspec
Add a stub Kernel#at_exit

By time it could become something real.
Support fake io output in nodejs runner

E.g. StringIO, that is used in the specs
Remove debug lines