Updated zstd to 1.1.0.

v1.1.0
New : contrib/pzstd, parallel version of zstd, by Nick Terrell
added : NetBSD install target (#338)
Improved : speed for batches of small files
Improved : speed of zlib wrapper, by Przemyslaw Skibinski
Changed : libzstd on Windows supports legacy formats, by Christophe Chevalier
Fixed : CLI -d output to stdout by default when input is stdin (#322)
Fixed : CLI correctly detects console on Mac OS-X
Fixed : CLI supports recursive mode `-r` on Mac OS-X
Fixed : Legacy decoders use unified error codes, reported by benrg (#341), fixed by Przemyslaw Skibinski
Fixed : compatibility with OpenBSD, reported by Juan Francisco Cantero Hurtado (#319)
Fixed : compatibility with Hurd, by Przemyslaw Skibinski (#365)
Fixed : zstd-pgo, reported by octoploid (#329)

(wiz)