更新主分支版本： build 521 rev 17 。

--HG--
branch : master
rename : YFramework/include/YSLib/Core/Cache.hpp => YBase/include/ystdex/cache.hpp
rename : YFramework/include/Helper/Host.h => YFramework/include/Helper/Environment.h
rename : YFramework/source/Helper/Host.cpp => YFramework/source/Helper/Environment.cpp