New pipeline-based commands and ES6

This release uses ES6 features and requires node 4+ to run

This release removes the nbt about command - this is contained within the build command.

The nbt build command (within make build-production) is required as it creates the slug to upload to Heroku. If your application does not have any js or sass you can add use nbt build --skip-js --skip-sass.

There is also 3 new commands to enable pipeline-based deploys:

• nbt drydock can be used to set up pipelines and apps on heroku with a single comand
• nbt float can be used in the provision step (it will create a new app deploy to it, run the __gtg checks and delete it)
• nbt ship Will run the configure scale and deploy tasks for pipelines