Merge pull request #36 from neocatalyst/gh-pages

Thanks for your contribution! We can set the navigation later.
Flow for concept: "Devhub is a drop-off service"
Flow for concept: Devhub hosts remote repositories
Added UI flows from @neocatalyst
Add code editor to “Devhub drop-off service” idea
Flow for concept: “Devhub is a tool - IDE”
HTML fix on Concepts page
Updated concepts diagram to elaborate idea

Many system behaviors are explained in detail. As a consequence, the
diagrams look more complicated than the last versions. The basic ideas
remain the same.
Added concept: “App Manager is Devhub”
Updated concepts to trim unnecessary steps
 resolve merge