v0.4.0

• Psr15Transport no longer consumes a non-seekable request body before the
  handler sees it (#36). A body that needs no parsing is not read at all: a
  seekable stream is rewound, a non-seekable one is passed through untouched.
  A form or multipart body on a non-seekable stream is buffered into a fresh
  seekable stream through the StreamFactoryInterface; without one the
  transport throws LogicException instead of handing over an exhausted
  stream. Previously every body was read up front and a non-seekable stream
  reached the handler at EOF.
• Requires rasuvaeff/property-testing-core ^0.5 || ^0.6 (was ^0.4, no
  longer supported) and, for development, rasuvaeff/property-testing-testo
^0.7 and rasuvaeff/understudy-testo ^0.2 (understudy core ^0.5).