Added basic steps to running a local distribution.

Hi, thanks for your contribution! :+1: 

The grunt build is not necessary to start developing I guess. The serve command will start live-reload as a mix static serve from .tmp and the source folder. If I recollect correctly when I set this up, the build is actually only for the sitedist (gh-page) and some preparation for the libdist task which will UMDfy and minify the library. This will need some cleanup at some point.

Can you test if it works fine without the grunt build to get started? If you please remove it from the contrib docs, and many thanks again for your contribution!

Cheers
Gion