Fixed the Windows IOCP backend 64Kb truncated reads and writes. Still got scatter-gather to fix though.
This improves the Windows IOCP backend significantly by fixing the 64Kb transfer limit, though VS2013 Preview keeps hanging during execution which may well be the Preview and not this code. I have failed after two attempts to fix the lack of multi-buffer support problem :( I may just have to completely write out all of ASIO's file handling code completely and go direct :(
Merge branch 'MSVC_build' of https://github.com/BoostGSoC/boost.afio into MSVC_build