The copyright and license notice is already in the LICENSE file. There
is no justifiable reason to also require that it be included in every
file, since the individual files are not individually distributed except
as part of the entire package.
This implements the user-facing APIs that lets one run a child process
and block until it exits.
Logic shared with the async counterpart of each function was refactored
to enable code reuse.
Docs and tests are included.
With -e or --eval, require() can load module using relative path.
node -e 'require("./foo")'
But it can't load module from node_modules directory.
node -e 'require("foo")'
Fixes#1196.