The troubled housing market saw some definite signs of improvement in the first quarter of 2012, a development that many mortgage lenders hope means that purchase-mortgage lending is finally ready to grow in 2012 following five years of declining volume. But tough mortgage underwriting requirements and even tougher lender overlays of additional standards are casting a dark shadow over the outlook for any significant surge in purchase-mortgage business this year. New numbers from the Campbell/Inside Mortgage Finance HousingPulse Tracking Survey show that the share of home purchases that were...