MD class structure:
~~~~~~~~~~~~~~~~~~~~
create class MD
  export:
  var Name      //""
  var ID        //0
  var Help      //0
  var Data      //nil
  var Idx       //1
  var CheckIt   //false
  var PreBlock  //{||true}
  var PostBlock //{||true}
  method New=MDNew   //o:New() --> self
  endclass