Add default styling

[kesla]

Currently this doesn't include very much styling. I think that it should be configurable to get the widget with good default styling.

[kesla]

@juliangruber Would like your input on this, do you think it's best that we have good styling always included or should that be configurable? It's a little bit tricky since good styling would include icons and stuff like that...

[juliangruber]

i like component's approach: provide structural styling so everything is aligned as it should be, and you get the idea, and maybe offer for example our style as a separate module