BOSTON - Dozens of gay couples rushed to tie the knot at chapels, parks and beaches across Massachusetts on Thursday as the end of the three-day waiting period under state matrimonial law led to a marathon of same-sex weddings. The Rev. Kim Crawford Harvie had barely retreated down the aisle with her wife of five minutes when she donned her white robes and got back to work at Arlington Street Church, marrying gay couples in assembly-line fashion. ''OK, I'm ready for my next couple!'' said Harvie, 46, who married her partner of seven years, Kem Morehead, at the Unitarian Universalist...