SPRINGFIELD — Illinois House Speaker Michael J. Madigan on Thursday called for removing statues and portraits of the 19th century U.S. Sen. Stephen A. Douglas from the statehouse along with other known slaveholders.“While reading Sidney Blumenthal’s book ‘All the Powers of Earth’ concerning the pre-Civil War period a few months ago, I learned of Stephen Douglas’ disturbing past as a Mississippi slave owner and his abhorrent words toward people of color,” the Chicago Democrat said in a statement. “I advised my staff to …