make "config" task into command-line utility

[mykmelez]

The "config" task, which configures auto-deploy via Travis, should be a command-line utility rather than a task, since you only ever need to run it once per app.

[mykmelez]

The task could also run when an app is created via Yeoman (#3) or via an Oghliner command for creating an app. Ideally, creating an app and configuring it to auto-deploy via Travis would be as simple as running commands like these and then following the prompts:

npm install -g oghliner
oghliner new my-app

[marco-c]

This was done in 6755e96, right?

[mykmelez]

Right!