Add frequently misspelled UK shops

See also this thread on the talk-gb mailing list:
https://lists.openstreetmap.org/pipermail/talk-gb/2014-December/016922.html
"Thomson" is a holiday chain in the UK so it's good to do this. However, since "Thompson" is a common British surname, and there are likely to be some other shops with this name, I think I would say that it's a bit too risky to automatically suggest Thompson->Thomson.

All the others look good to me, good fixes!