function linkFromGlobal (cwd, name) {
	const dst = path.join(cwd, 'node_modules', name)
	const src = path.join(config.globalNodeModules, name)
	return forceSymlink(src, dst)
}
links a globally linked package into the package present in the current
working directory (used for `ied link some-package`).
the package can be `require`d afterwards.
`node_modules/.bin` stays untouched.
@param {String} cwd - current working directory.
@param {String} name - name of the dependency to be linked.
@return {Observable} - observable sequence.