Merge pull request #83 from pandamicro/v3_assets_manager

Fixed #5869: Fix ccui.Layout doesn't sort children nodes with their local z order
modify wirtable path
Merge pull request #84 from chuanweizhang2013/v3_assets_manager

modify wirtable path
Fixed #5903: Fixed stroke color issue of LabelTTF on iOS
Issue #5892: Polish AssetsManager