Earnings fall short as the housing market slows.Residential land developer Forestar Group (FOR -15.32%) delivered results that fell short of expectations and provided little reason for investors to get excited about the quarters ahead.Wall Street is taking note, sending Forestar shares down 15% as of 11:15 a.m. ET.Sluggish demandForestar isn't a home builder, but it is tied closely to the industry. The company, which is majority-owned by D.R. Horton, acquires and develops lots in 60 markets across 24 states ...