CCTileMapInfo: Fix overflow issue when decoding base64 tile map data
CCTileMapInfo: Fix overflow issue when decoding base64 tile map data

* Using left-shift operator on byte when it should be cast to uint first

TukekeSoft/CocosSharp,mono/CocosSharp,TukekeSoft/CocosSharp,mono/CocosSharp,MSylvia/CocosSharp,zmaruo/CocosSharp,haithemaraissia/CocosSharp,MSylvia/CocosSharp,zmaruo/CocosSharp,haithemaraissia/CocosSharp