Providing ports, renaming parameters, honoring interpreter

embedded script handling

Squashed commit of the following:

commit d00c7e444d55ffe227fe520c2b5a53ec35daa666
Author: Thomas Schank <DrTom@schank.ch>
Date:   Sat Nov 30 21:26:53 2013 +0100

    Honoring interpreter parameter of script

commit d5016481bb351ee0bc0e572038e801cccd32baf5
Author: Thomas Schank <DrTom@schank.ch>
Date:   Sat Nov 30 18:26:42 2013 +0100

    Providing ports on a trial basis

commit e992493c18eebe3f2c47f357125899ebf69d82dd
Author: Thomas Schank <DrTom@schank.ch>
Date:   Sat Nov 30 16:42:40 2013 +0100

    Refactored script handling (embedded)

    and renamed env_vars to environment_variables

commit 524f7db1e1a2840bb7ddb52a5487b98a20ad07a4
Author: Thomas Schank <DrTom@schank.ch>
Date:   Wed Nov 27 09:00:39 2013 +0100

    Added port_provider