Make configs separate and return a deferred object

Little code to do two things:

- put config.js as a separate file that's not checked into repo with secrets, etc.

- sendpush now returns a deferred object and resolves / rejects. Not sure how exactly to handle resolve / rejecting with the apn push, so for ios, it currently always resolves after sending the push, but for android, it should resolve and reject appropriately. The promise that's returned could be useful for a function calling sendpush internally.

Let me know if any of this seems like a bad idea :)
Thanks!