Upstream Changelog: * Preliminiary HTTP2 support for http\Client (libcurl with nghttp2 support) * Improved performance of HTTP info parser (request/response line) * Improved performance of updating client observers * Improved performance of http\Env\Response output to streams * Improved the error messages of the header parser * Added http\Header\Parser class * Added http\Client::configure() method accepting an array with the following options for libcurl: * maxconnects (int, size of the connection cache) * max_host_connections (int, max number of connections to a single host, libcurl >= 7.30.0) * max_pipeline_length (int, max number of requests in a pipeline, libcurl >= 7.30.0) * max_total_connections (int, max number of simultaneous open connections of this client, libcurl >= 7.30.0) * pipelining (bool, whether to enable HTTP/1.1 pipelining) * chunk_length_penalty_size (int, chunk length threshold for pipelining, libcurl >= 7.30.0) * content_length_penalty_size (int, size threshold for pipelining, libcurl >= 7.30.0) * pipelining_server_bl (array, list of server software names to blacklist for pipelining, libcurl >= 7.30.0) * pipelining_site_bl (array, list of server host names to blacklist for pipelining, libcurl >= 7.30.0) * use_eventloop (bool, whether to use libevent, libcurl+libevent) * Added http\Client::getAvailableOptions() and http\Client::getAvailableConfiguration() methods * Added support for HTTP2 if libcurl was built with nghttp2 support. * Added http\Client\Curl\HTTP_VERSION_2_0 constant (libcurl >= 7.33.0) * Added http\Client\Curl\TLS_AUTH_SRP constant (libcurl >= 7.21.4) * Added pinned_publickey SSL request option (libcurl >= 7.39.0) * Added tlsauthtype, tlsauthuser and tlsauthpass SSL request option (libcurl >= 7.21.4) * Added verifystatus (a.k.a OCSP) SSL request option (libcurl >= 7.41.0) * Added proxyheader request option (libcurl >= 7.37.0) * Added unix_socket_path request option (libcurl >= 7.40.0) * Fixed compress request option * Fixed parsing authorities of CONNECT messages * Fixed parsing Content-Range messages * Fixed http\Env\Response to default to chunked encoding over streams * Fixed superfluous output of Content-Length:0 headers * Fixed persistent easy handles to be only created for persistent multi handles * Fixed the header parser to accept not-yet-complete header lines * Fixed http\Message::toStream() crash in ZTS mode * Fixed the message stream parser to handle intermediary data bigger than 4k * Fixed the message stream parser to handle single header lines without EOL * Fixed http\Message\Body to not generate stat based etags for temporary streams * Deprecated http\Client::enablePipelining(), use http\Client::configure(["pipelining" => true]) instead * Deprecated http\Client::enableEvents(), use http\Client::configure(["use_eventloop" => true]) instead * Removed the cookies entry from the transfer info, wich was very slow and generated a Netscape formatted list of cookies * Changed the header parser to reject illegal characters