Bug #4978: fix  Z vertex bug of TileMapTest
Bug #4978: use an object to cache the extended members
Merge pull request #360 from joshuastray/master

Bug #4978: fix  Z vertex bug of TileMapTest
Feature #4546: Add android "back" key support to JSB
Merge pull request #361 from joshuastray/master

Feature #4546: Add android "back" key support to JSB