nghttp2 v1.15.0

• lib: Add nghttp2_option_set_max_deflate_dynamic_table_size() API function (GH-684)
• lib: Allow NGHTTP2_ERR_PAUSE from nghttp2_data_source_read_callback (GH-671)
• lib: Add nghttp2_session_get_hd_deflate_dynamic_table_size() and nghttp2_session_get_hd_inflate_dynamic_table_size() API functions to get current HPACK dynamic table size (GH-664)
• lib: Add nghttp2_session_get_local_settings() API function (GH-664)
• lib: Add nghttp2_session_get_local_window_size() and nghttp2_session_get_stream_local_window_size() API functions (GH-664)
• build: Add -lsocket -lnsl to APPLDFLAGS for solaris build (GH-674)
• neverbleed: Update neverbleed to support ECDSA certificate
• doc: Mention --enable-lib-only configure option in README
• integration: Fix test failure with go1.7.1
• src: Fix compile error with openssl 1.1.0
• nghttpx: Improve performance with HTTP/1.1 backend when request body is involved
• nghttpx: Use std::atomic_* overloads for std::shared_ptr if available
• nghttpx: Migrate backend stream to another h2 session on graceful shutdown
• nghttpx: Add option to specify HPACK encoder/decoder dynamic table size
• nghttpx: Log client address
• nghttpx: Add tls_sni to mruby Nghttpx::Env class
• nghttpx: Add --frontend-http2-window-size option, and its family functions
• nghttpx: Add experimental TCP optimization for h2 frontend
• nghttpx: Workaround for std::make_shared bug in Xcode7, 7.1, and 7.2 (GH-670)
• nghttpx: Fix bug that bytes are doubly counted to rate limit for TLS connections
• nghttpx: Add --no-server-rewrite option not to rewrite server header field (GH-667)
• nghttpx: Retry if backend h1 connection cannot be established due to timeout
• nghttpx: Reset stream if invalid header field is received in h2
• nghttpx: Add --server-name option to change server response header field (GH-667)
• nghttpd: Add --encoder-header-table-size option
• nghttp: Add --encoder-header-table-size option
• python: Support ALPN, require Python 3.5