Adding missing music for the Dwarves.

Hello! I've noticed for a while that the Dwarves, a race that is so great in practical and musical terms, are missing some music tracks, namely the tavern (which uses the city theme), hiring creatures (also using the city theme), and escaping from battle (which has nothing assigned at all). So, I decided to do some editing and cut up the existing tracks to fill in the missing parts (except, perhaps, for the victory and defeat themes of the campaign. I don't think that makes sense - they only have one campaign, and it uses the rather beautiful themes from the Knight campaign).