previewer: d3js csv previewer

* Adds d3js csv previewer.

Signed-off-by: Adrian Pawel Baran <adrian.pawel.baran@cern.ch>
Please sort imports http://legacy.python.org/dev/peps/pep-0008/#imports

> Imports should be grouped in the following order:
>
> 1. standard library imports
> 2. related third party imports
> 3. local application/library specific imports