Competition starts Tuesday at the Eurovision Song Contest, with divisions over Israel 's participation hanging over the 70th birthday of the over-the-top pop music extravaganza. Host city Vienna has been bedecked in hearts and the contest’s “United by Music” motto for a week in which singers and bands from 35 countries will compete onstage for the continent’s musical crown. But five countries — Spain , Ireland, the Netherlands, Slovenia and Iceland — are boycotting to protest Israel's inclusion. Several pro-Palestinian demonstrations are planned in Vienna during Eurovision week, and security is tight, with police officers from across Austria deployed in the capital, and support from forces in neighboring Germany.…