Convert screencast of getting-started to markdown

[jvasile]

This addresses #2 and the plea in the current version of docs, which says:

Contribution needed: We would like to add a written getting started guid here. 

As a step toward a written getting started guide, I converted the screencast to markdown, then adjusted it a bit for easier digestion. That should give people something to follow that they can read at their own pace and from which they can copy text.