adding images
Adding an introduction and overview.
Adding line breaks to the markdown. <br>
Update etcd.md
Update etcd.md
Update etcd.md
Create introduction.md
Update introduction.md
adding some helpful etcd links.
Fix some minor typos
Merge pull request #41 from lytics/esniff_docs_branch

Committing this for now, but I need to fix my grammar mistake in the SVG image.