overload function tip

convert args to luatype store in longlong, so overload functor only can hold func with diffrent signatur`  
void(int) = LUA_TNUMBER = 0x3, void(double) = LUA_TNUMBER = 0x3, they have the same signature,
void(int,a*) = LUA_TNUMBER,LUA_TUSERDATA = 0x73 , void(long long,b*) = LUA_TNUMBER,LUA_TUSERDATA = 0x73 , they have the same signature,
we use longlong to stroe,so we only support 16 args