Comment fixed.

Comment fixed.
(MAX_MAP_SET_LEVEL): Increased to 30.
(PUSH_MAPPING_STACK): Enclose with do-while block.
(POP_MAPPING_STACK): Likewise.
(stack_idx_of_map_multiple): New variable.
(CCL_CALL_FOR_MAP_INSTRUCTION): New macro.
(ccl_driver) <CCL_IterateMultipleMap>: If the content is a symbol,
call the corresponding CCL program by
CCL_CALL_FOR_MAP_INSTRUCTION.
(ccl_driver) <CCL_MapSingle>: Likewise.
(ccl_driver) <CCL_MapMultiple>: Rewritten to fix many bugs, deal
with the case where looking up process reaches to the end of
map-set, and call CCL programs as the above change.