Changed capistrano version to 3.1.0 since there was a conflict with capistrano-rails which is using capistrano -v3.1.0.

Also, fix the space bug for capture command.
Bump up the version.
Make it use app name and license key from newrelic.yml - they'll be there anyway.
Use stage as default environment. Was previously using local stage, which doesn't make sense in a multistage deployment.
Bump version.