code: func opcodeLessThan(op *parsedOpcode, vm *Engine) error {
  	v0, err := vm.dstack.PopInt()
  	if err != nil {
  		return err
  	}
  
  	v1, err := vm.dstack.PopInt()
  	if err != nil {
  		return err
  	}
  
  	if v1 < v0 {
  		vm.dstack.PushInt(scriptNum(1))
  	} else {
  		vm.dstack.PushInt(scriptNum(0))
  	}
  
  	return nil
  }
docs: // opcodeLessThan treats the top two items on the data stack as integers.  When
  // the second-to-top item is less than the top item, they are replaced with a 1,
  // otherwise a 0.
  //
  // Stack transformation: [... x1 x2] -> [... bool]