1.4.0

version 1.4.0

Changes since 1.3.3:

• The C implementation provides a CMakeLists.txt for callers who build
  with CMake. The CMake build is not yet stable, and callers should
  expect breaking changes in patch version updates. The "by hand" build
  will always continue to be supported and documented.
• b3sum supports the --seek flag, to set the starting position in
  the output stream.
• b3sum --check prints a summary of errors to stderr.
• Hash::as_bytes is const.
• Hash supports from_bytes, which is const.