tilemap supports XML layer format
the latest develop code merged
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-x into tilemap_plain_xml_format_support
added _currentTileIndex member to TMXLayerInfo
removed extra _currentTileIndex
Merge branch 'tilemap_plain_xml_format_support' of https://github.com/simpliplant/cocos2d-x into tilemap_plain_xml_format_support and add extra control to parse the tmx file for load the xml format tiles.
Merge pull request #3420 from boyu0/tilemap_plain_xml_format_support

Support for loading tilemaps with plain XML layer format