test-helper does not read settings.js

At the moment it is impossible to test a flow which has a function node, which loads a module with a call to global.get(). (See the documentation on loading modules in function nodes.)

Reason is that the test helper doesn't read a settings.js file in index.js:159.

I don't think test-helper should be reading a settings file - but it should let you provide a settings object as part of the api.