Bug 1000718 - Add basic local storage. r=mshal
Bug 1000718 - Avoid requiring boto when not using S3 storage. r=mshal
Bug 1000718 - Create hierarchy at the storage level instead of when creating the key. r=mshal

Also, use a two-level hierarchy for local storage
Bug 1000723 - Allow to store more than one object file in CacheData, and add stderr. r=mshal
Bug 1000723 - Also store stdout in cache (MSVC likes writing there). r=mshal
Bug 1000723 - Add generic support for multiple output from compilation. r=mshal
Bug 1000730 - Add stats for failures to cache. r=mshal
Bug 1000728 - Add support for -gsplit-dwarf on GCC. r=mshal
Bug 1000726 - Add support for -Zi -Fd with MSVC. r=mshal
Bug 1000731 - Avoid process pool creating windows for each new process on Windows. r=mshal