issue #3025: add getTextureCache() in CCdirector()
issue #3025: Deprecate TextureCache::getInstance() destroyInstance()
issue #3025: replace TextureCache::getInstance() by Director::getInstance()->getTextureCache() in cocos folder
issue #3025: replace TextureCache::getInstance() by Director::getInstance()->getTextureCache() in samples folder
issue #3025: remove TextureCache::_sharedTextureCache
Merge branch 'develop' of github.com:cocos2d/cocos2d-x into iss3025_TextureCache
issue #3025: move VolatileTexture static function to VolatileTextureMgr
issue #3025: deprecate TextureCache::reloadAllTextures, call VolatileTextureMgr::reloadAllTextures instead
issue #3025: directly use _textureCache in Director
Merge pull request #4160 from dabingnn/iss3025_TextureCache

[ci skip]Iss3025 texture cache