Winter can be dark, dull and depressing. The long nights, the bone chilling frosts. If winter was a genre of music it would most obviously be bubblegum pop. Irritating, needless and wished by all the cool kids, the world over, to end as soon as possible. Yet the analogy also works on two levels. Crank up a bit of feel-good indie rock or a ferocious bit of the hard stuff and the winter needn’t be too depressing. Couple that action with a visit to some of Europe’s greatest rock n’roll cities and the feeling gets even lighter. Now we’re going…