add root resource + some minor cleanup

/api now responds with a root resource, containing links to /api/customer, /api/employee, /api/project. I ignored everything under /api/mongo for now, I suspect this will be moved to /api eventually when the mock data is no longer used?

I also removed some grunt related stuff from package.json, as far as I can see, there is no Gruntfile yet, amirite?

Also I accidentally overwrote `.gitignore` :-) but when I was about to revert that change I wondered where all this unrelated clutter came from (Eclipse, Visual C++, Python and whatnot). I think it's okay to get rid of that. Ping me if you would rather keep the former version, I'll revert `.gitignore` to the original state and add the revert to the PR.