Declare dun-line and dun-line-list

Declare dun-line and dun-line-list

Previously, there were free variables 'line' and 'line-list'.
* lisp/play/dunnet.el (dun-line, dun-line-list): New variables.
(dun-press, dun-vparse, dun-parse2, dun-unix-parse, dun-batch-parse):
(dun-batch-parse2, dun-batch-loop, dun-batch-dos-interface):
(dun-batch-unix-interface): Use them.