Fix ey_config YAML.

It seemed to be broken with this error:

/home/jon/rollbar/rollbar-rails-demo/vendor/bundle/gems/ey_config-0.0.6/lib/ey_config.rb:99:in `find_config': Expected to find EY::Config YAML file at one of: ["/home/jon/rollbar/rollbar-rails-d
emo/config/ey_services_config_deploy.yml", "/home/jon/rollbar/rollbar-rails-demo/config/ey_services_config_local.yml"] (ArgumentError)
Update rollbar-gem version to 1.2.13.
Update rollbar.js.
Use Rollbar.scope instead of Rollbar[level] to set the correct report level.
Merge pull request #11 from rollbar/update-versions

Update notifiers to latest versions.