added jackson dependency to pom
added jackson dependency to pom

strubell/factorie,joprice/factorie,factorie/factorie,digitalreasoning/factorie-scala-210,patverga/factorie,pogren-oracle/factorie,Craigacp/factorie,melisabok/factorie,malcolmgreaves/factorie,zxsted/factorie,asubbaswamy/factorie,hlin117/factorie