Changes in the warning system

- The warning functions get an extra parameter that tells whether
message is to be continued (instead of using end-of-lines as a signal).

- The user data for the warning function is a regular value, instead
of a writable slot inside the Lua state.

lstate.h

@@ -317,7 +317,7 @@ LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L);
 LUAI_FUNC void luaE_freeCI (lua_State *L);
 LUAI_FUNC void luaE_shrinkCI (lua_State *L);
 LUAI_FUNC void luaE_enterCcall (lua_State *L);
-LUAI_FUNC void luaE_warning (lua_State *L, const char *msg);
+LUAI_FUNC void luaE_warning (lua_State *L, const char *msg, int tocont);
 
 
 #define luaE_exitCcall(L)	((L)->nCcalls--)