It's 4 years since Anders Behring Breivik murdered 69 people on the Norwegian island of Utoya. The victims were taking part in the annual Labour party youth summer camp. This year, for the first time since the massacre, the youth camp has returned. Lisbeth Röyneland lost her daughter Synne and now chairs the national support group for survivors. Emma Wallis talks to her about 'taking back' Utoya.