add Eclipse Help that is written in markdown and converted into HTML by this plugin.

add Eclipse Help that is written in markdown and converted into HTML by this plugin.

the `src/site/markdown` folder maybe a bit long, but it is folder for maven generated site,
e.g. http://dev.nodeclipse.com/

I wanted to changed icons on View first `back`, then `forward` as standard in browser.
But now tired. Maybe next time or you can possibly fix that in a minute, when changing code next time.