DOC: contributing and usage guides

[bsipocz]

We will need to write up some short documents for 1) contributing to this repo; as well as 2) bulk usage; e.g. cloning the whole repo either into a SP environment, or directly by the users (as opposed to pick and choose from the HTML renderings).

In order to keep the repo clean of random branches, I would suggest following a fork based workflow for contributing.