nghttp2 v1.17.0

• lib: Disallow content-length in 1xx, 204, or 200 to a CONNECT request (GH-722)
• lib: Avoid memcpy against NULL src
• build: MSVC version resource support (Patch from Remo E) (GH-718)
• asio: server: Call on_close callback on connection close (GH-729)
• nghttpx: Fix frequent crash with --backend-http-proxy-uri
• nghttpx: Robust backend read timeout
• nghttpx: Fix bug that mishandles response header from h1 backend
• nghttpx: Fix bug that zero-length POST is not forwarded (GH-726)
• nghttpx: Remove optional reason-phrase from SPDY :status
• nghttpx: Header key and value must be string in mruby script
• nghttpx: Strip content-length with 204 or 200 to CONNECT in mruby (GH-722)
• nghttpx: Strict handling for Content-Length or Transfer-Encoding in h1 (GH-722)
• nghttpx: Fix compilation with BoringSSL (Patch from dalf) (GH-717)
• nghttpd, nghttpx, asio: Add missing mandatory SP after status code