Grim tales of jailbirds, cutthroats, cuckolds, executioners, murderers and escapees.  Prison ballads form part of the historic lifeblood of Country Music and saw a resurgence after the 1960 execution of controversial convict Caryl Chessman. Here are some of the very best, seldom heard since their original release. Running the gamut from smooth balladeers of woe to ramshackle …