Since all headers are not always longer available on one
nghttp2_session_mem_recv call, received headers may be interleaved
with transmission log of the other frames. To make it clear that
each header belongs to which stream, each header is printed with
stream_id.

nghttp2_data is added to nghttp2_frame union. When DATA is
received, nghttp2_on_frame_recv_callback is called. When DATA is
sent, nghttp2_on_frame_send_callback is called.

This is a preparation to add public nghttp2_data struct to
nghttp2_frame union.

The maximum frame size including header block is still limited
to NGHTTP2_HD_MAX_BUFFER_LENGTH, which is 32KB.

Now incoming data is processed in very small buffer (up to 8 bytes)
using state machine. GOAWAY debug data can get to 16K - 1, and we
don't have callback for it. Since we don't want to buffer that
amount of data just for debugging, we currently discard it.
This change also makes parse_error callback not function.
It probably be removed from API.

This stream inflater can inflate incoming header block in streaming
fashion. Currently, we buffer up single name/value pair, but we chose
far more smaller buffer size than HTTP/2 frame size.

evdns_base uses /etc/resolve.conf for *nix like systems,
but all platforms don't have the file (e.g., android device).
For such platforms, address resolution fails.
To fix this problem we use getaddrinfo() directly.

And other renames.

4ed4efc2 does not disable TLS renegotiation at all, if client keeps
rengotiations without sending application data. In this change,
we intercept the raw incoming data from the client and if it is a
renegotiation, drop the connection immediately.