Leading header must be an h1 header.
Moved introductory article into articles/00-intro/ so that it's a peer article of the other chapter intros.
Moved introductory article into articles/00-intro/ so that it's a peer article of the other chapter intros.
Remove introduction. Intro from 01-what-is-liferay/ should suffice.
Merge pull request #956 from jhinkey/use-content

User Guide - fix and adjustment