update admin.txt

add a chinese language
Update adminchat.txt
Update admincmd.txt
Update adminhelp.txt
Update adminslots.txt
Update adminvote.txt
Update antiflood.txt
Update cmdmenu.txt
Update common.txt
Update imessage.txt
Update languages.txt
Update mapchooser.txt
Update mapsmenu.txt
Update mapsmenu.txt
Update menufront.txt
Update miscstats.txt
Update multilingual.txt
Update timeleft.txt
Update time.txt
Update telemenu.txt