Ask for 200 songs from the iTunes API

Fixes #3 (for now.)

This is a hack and not a fix as it won't work for releases which
have more than 200 songs. Until then...

I wish the API had a 'more' field giving the link to next call or
something like that.

iTunes API Docs are here:
https://www.apple.com/itunes/affiliates/resources/documentation/itunes-store-web-service-search-api.html