Casper ter Kuile lights a candle in front of his computer screen. And then the music begins.All around the world, linked by video, more than 100 people sing “Come, Come Whoever You Are,” lyrics adapted from a poem by Rumi, the 13th century Sufi mystic. Then, laughing together, “Kookaburra,” the Australian nursery rhyme. And then, in Hebrew, “Hinei Matov.””How good and how pleasant it is