A new plan by the Los Angeles Unified School District would extend by one year the rollout of a $1 billion school iPad program. The Los Angeles Times says the slowdown in providing every student in the district with one of the tablet computers is a concession to critics inside and outside the system who questioned whether officials had been pushing too fast in distributing about 650,000 devices to teachers and students. Problems quickly emerged this fall dL.A. uring efforts to provide the devices to 47 campuses