(fix) Reintroducing the usage of NODE_ENV

Now the default behaviour is to start the server in dev mode.
In dev mode specifying a documentation-code fodler is mandatory.
Then you can override everything related to framework at command line level.

You also have the ability to override framework version and skin dynamically from the query
Merge pull request #14 from benouat/commandLineParams

Reintroducing the usage of NODE_ENV