• Fixes an invalid assumption that could happen when using the
  -e, --filter-error option with "fix" or "check".
  This was triggered by a very specific pattern of fragmented files
  and bad blocks combination, not so easy to reproduce.
  This had no bad effect, if not preventing the command to run.
• Drastically reduces the memory usage. For each block, it now
  uses 17 bytes of memory, instead of the previous 28 bytes
  (for 32 bit) or 36 bytes (for 64 bit).
  This could result is a memory saving of up the 50%.
• The -p, --plan option (old --percentage) can be used to
  define a scrub plan: "new", "bad" and "full".
  The "new" plan scrubs all the new synced blocks not yet scrubbed.
  This allows to verify as early as possible that the written
  parity during sync is really correct. You can use the "status"
  command to show the amount blocks not yet scrubbed.
  The "bad" plan scrubs only bad blocks.
  The "full" plan scrubs all blocks.
• The graph in the "status" command now show scrubbed blocks
  with '*', and synced, but not yet scrubbed, blocks with 'o'.
  Note that when upgrading from a previous version, all blocks
  are assumed scrubbed the first time.
• Content files are now written asyncronously from different
  threads to avoid the unfortunate condition that a memory
  error affects all of them in the same way.
  After writing, they are read again to verify their CRC.
  This is done to ensure thay they are really OK, even in the
  case of the worst possible silent errors.
• Extends the -D, --force-device option to ignore more
  erroneous conditions in the 'fix' command, like unaccessible
  disks, or disks sharing the same physical device.
• Extends the -d, --filter-disk option to allow to filter also
  by parity disk.
• Extends the -h, --pre-hash option to also verify moved and
  copied files into the array before running a 'sync'.
• Updates 'best' RAID functions for recent Atom CPUs.
• Validates filters specifications rejecting relative paths.