Call on_data_chunk_recv_callback only when stream is active
nghttpx: Reduce socket I/O buffer size
Reduce huffman decoding table

Previously we have uint16_t as state member variable in
nghttp2_huff_decode structure to express -1 as failure.  This is
because we have 256 valid states.  However, we can express failed
state using flags member variable and make state uint8_t.  This commit
does this and as a result the size of decoding table is reduced.
Add note to manual how to submit frames to new stream ID
nghttpx: Set timeout to underlying bufferevent

Setting write timeout to filter bufferevent does not work as intended.
It timeouts even when there is no data to write.
nghttpx: Fix typo
nghttpx: Lower read watermark
src: Avoid copy in evbuffer_pullup()

Previously, we use evbuffer_pullup(buf, -1) to linearize the memory
region and it may cause buffer copy.  To avoid this, we use the return
value of evbuffer_get_contiguous_space() as 2nd parameter.  According
to the libevent manual, by doing so evbuffer_pullup() will not copy or
modify any data in evbuffer.
nghttpx: Code cleanup

Mainly make nested code block to rather flat style.
Update doc
Bump up version number to 0.4.1, LT revision to 3:1:0
Update man pages
Bump up version number to 0.4.2-DEV
Merge branch 'Wshadow' of https://github.com/alagoutte/nghttp2 into alagoutte-Wshadow
deflatehd: Fix crash with -t option
h2load: Return Stats rather than Worker from std::future
h2load: Use 1 thread if the number of concurrent client is 1
nghttpx: Disable SSL_CTX_set_ecdh_auto() for now
Fix off-by-one error when computing padding
nghttpx: Use std::unique_ptr<char[]> instead of char*