Summary:
- You can now pass `--config-dir-path=/some/custom/path` to `./N1.sh`
- `main.coffee` cleaned up a bit. A lot of unused params from legacy Atom
stuff were still being used
- Integration specs now set the config dir before booting.
- New spec to check for the autoupdater in the app and make sure it's
pointing at the right place.
Test Plan: script/grunt run-integration-tests
Reviewers: juan, bengotow
Reviewed By: bengotow
Differential Revision: https://phab.nylas.com/D2331
