Merge pull request #48 from pandamicro/lua-vm

Using curl_multi_perform in batchDownload, Add getFailedAssets, updateAssets function and improve error handling
Feature #4977: Refactor success callback of Downloader, remove thread pool
Feature #4977: Add compressed key parsing for Asset in Manifest
Feature #4977: Add decompress process in AssetsManager
Feature #4977: Add Error decompress in EventListener
Merge branch 'lua-vm' of https://github.com/dumganhar/cocos2d-x into lua-vm
Feature #4977: Add AssetsManager dependencies into CMakeList
Feature #4977: Improve decompress function
Feature #4977: Fix decompress path issue
Feature #4977: Add implementation of real progression
Feature #4977: Improve implementation of real progression
Feature #4977: Add AssetsManager::downloadFailedAssets API
Feature #4977: Take account of FOPEN_MAX
Feature #4977: Ignore file level progression
Feature #4977: Improve decompress : create directory only when needed
Feature #4977: Improve AssetsManager test case
Feature #4977: Add fopen fclose logs
Feature #4977: add fclose for zip next file fail error