Update bootstrap.wicket.css

Added right/left padding of 10px to the media-object class for the wicket theme.

This handles the text butting right up against the image as shown in the live demo:
http://wb.agilecoders.de/demo/components?theme=wicket#media

See wicket-bootstrap Issue #229 at:
https://github.com/l0rdn1kk0n/wicket-bootstrap/issues/229