The object cache implementation is XL cache, which defaults
to 8GB worth of read cache. Currently GetObject() transparently
writes to this cache upon first client read and then subsequently
serves reads from the same cache.
Currently expiration is not implemented.
* xl/ListFiles: return as many objects as requested and take care of eof (#1361)
* xl/ListFiles: fix review comments.
* xl/ListFiles: Add windows filepath translation.
* xl/ListFiles: Use slashSeparator instead of "/". Remove filepath.FromSlash() as golang-windows takes care of it automatically.