Adds LiveScript boilerplate support :)

Added boilerplates for livescript and tweaked bin/lib/derby.js to be a little more flexible for further boilerplates down the line (but could easily be further improved and better encapsulated).

Was tested as follows...

```
kmandrup:derby (master) $ bin/derby --livescript new mylife

  Creating LiveScript project in mylife with the application app

  created: /Users/kmandrup/private/derby-projects/derby/mylife
  created: /Users/kmandrup/private/derby-projects/derby/mylife/src
  created: /Users/kmandrup/private/derby-projects/derby/mylife/styles
  created: /Users/kmandrup/private/derby-projects/derby/mylife/ui
  created: /Users/kmandrup/private/derby-projects/derby/mylife/views
  created: /Users/kmandrup/private/derby-projects/derby/mylife/.gitignore
  created: /Users/kmandrup/private/derby-projects/derby/mylife/Procfile
  created: /Users/kmandrup/private/derby-projects/derby/mylife/README.md
  created: /Users/kmandrup/private/derby-projects/derby/mylife/package.json
  created: /Users/kmandrup/private/derby-projects/derby/mylife/server.ls
```