面板记忆：大小位置的本地留存

-- 错误：每次打开都回默认，布局日日重摆
function openPanel()
    panel:setPosition(DFT_X, DFT_Y)
    panel:setVisible(true)
end

local VERSION = 2
local function openPanel()
    local saved = readLocal("layout_v" .. VERSION)
    if saved ~= nil then
        panel:setPosition(saved.x, saved.y)
        panel:setContentSize(cc.size(saved.w, saved.h))
    end
    panel:setVisible(true)
end
local function onPanelMoved(x, y, w, h)
    writeLocal("layout_v" .. VERSION,
        {x = x, y = y, w = w, h = h})
end