Fix: Ignore excessive whitespace in chunk header for Transfer-Encoding: chunked
(#123 by @DangerLifter and @clue)

Fix: Ignore invalid incoming Transfer-Encoding response header
(#122 by @clue)

Improve documentation for Client (and advanced Connector)
(#111 by @jsor and #121 by @clue)

Improve test suite by adding support for PHPUnit 6
(#112 by @carusogabriel)