State Estate Tax Changes    The Wills, Trusts, and Estates Prof Blog reports that the federal estate tax exemption was indexed for 2012, increasing the $5 million exemption to $5.12 million. Many of the twenty-three states, including Washington, D.C., that impose state estate taxes have also made changes for 2012. A list of state specific changes to estate taxes for 2012 and beyond is below: To keep up with inflation, North Carolina and Rhode Island increased their exemptions to $5.12 million and $892,865, respectively. Illinois increased its exemption from $2 million in 2011 to $3.5 million beginning January 1, 2012.…