More responsive article layout, still quite a way to go - but image moves nicely.

Next tasks:
- observable and sorting after vote up / vote down on item
- make show comments visible again
- Allow adding of image, if mimetype of URL is not an image
- JavaScript: dependency injection for data service
- JavaScript: better design for article & comments factory
- JavaScript: clean up articleviewmodel (do not extend, when overriding quite some properties anyway)