Executes the command specified as a shell command.   The name of the system
command can be changed in tintin.h for your security.
NEW from ytin1.80:
#system {command} {option}
options: (default is 0)
For Windows NT/2000:
0: try to hide output window, capture output by > tintin.out, then display
   in ytin windows (can action on the message)
1: try to hide output window, do not add > tintin.out
2: do not try to hide output window, capture output by > tintin.out
3: do nothing, old tintin++ behavior
For Unix/Windows 95/98:
0,2: capture output by > tintin.out, then display in ytin window (can
      action on the message.)
1,3: do nothing, old tintin++ behavior.
Notice: if use some commands like vi, please specify option {3}.