修正联网模式可以F8+F4

整理代码，游戏场景不再有自己的tasUsed变量

Zframework/init.lua

@@ -234,11 +234,13 @@ local function noDevkeyPressed(key)
     elseif key=="f3"then
         MES.new('error',"挂了")
     elseif key=="f4"then
-        for _=1,8 do
-            local P=PLY_ALIVE[rnd(#PLY_ALIVE)]
-            if P and P~=PLAYERS[1]then
-                P.lastRecv=PLAYERS[1]
-                P:lose()
+        if GAME.playing and not GAME.net then
+            for _=1,8 do
+                local P=PLY_ALIVE[rnd(#PLY_ALIVE)]
+                if P and P~=PLAYERS[1]then
+                    P.lastRecv=PLAYERS[1]
+                    P:lose()
+                end
             end
         end
     elseif key=="f5"then