Convert Snapbird to Node

WIP

## Todo

- [ ] Check existing functionality
- [ ] Remove 'custom' urls (hitting `proxy.php`) from front-end
- [ ] Front end to access `/api/user` for access token
- [ ] Restore twitterlib as submodule (currently on cdnjs)
- [ ] Use access token with twitterlib to restore full functionality
- [ ] Automated tests?