Zstandard v0.7.2

fixed : ZSTD_decompressBlock() using multiple consecutive blocks. Reported by @GregSlazinski
fixed : potential segfault on very large files (many gigabytes). Reported by @chipturner
fixed : CLI displays system error message when destination file cannot be created (#231). Reported by @chipturner
fixed : leak in some fail scenario in dictionary builder, reported by @nemequ