Update hellognome.js to use WebKit2, sync snippets and full code example.

Edits for the hellognome example found here:

https://developer.gnome.org/gnome-devel-demos/stable/hellognome.js.html.en

It needs to use WebKit2 rather than WebKit to run properly.

Additionally, the code snippets in the article used the Lang.Class and Lang.Bind utilities which were not used in the more modern full code example at the end of the article. The snippets have been updated to match the final example source, along with the text where necessary.

Also added a <meta charset="utf-8"> tag to the HTML which is pretty essential these days.