If there was a collective shriek of horror from soon-to-be-moms when Manayunk’s Belly closed in 2008, there was an equally loud sigh of relief when Chelsea Ivsin and Elizabeth Long, then-employees of the store, kept the lease and reopened last May — all during their senior year at Philadelphia University. Their selection of flattering, easy-to-wear maternity clothes, handbag-pretty diaper bags and It strollers has us just as impressed as the story of how their shop came to be.