This may be useful to the misbehaving implementation, but it could
result in lots of RST_STREAM, so just ignore it for now.

Add this check in nghttp2_submit_{priority, window_update, data,
push_promise}.

Simply it does not work as expected.

Now NGHTTP2_OPT_NO_AUTO_WINDOW_UPDATE is split into 2 options:
NGHTTP2_OPT_NO_AUTO_STREAM_WINDOW_UPDATE and
NGHTTP2_OPT_NO_AUTO_CONNECTION_WINDOW_UPDATE.
This is preparation for the upcoming removal of END_FLOW_CONTROL
flag. For nghttpx, instead of using END_FLOW_CONTROL to disable
connection-level flow control, increase window size by large
enough value, which is friendly way to current chromium
implementation.

Rename window_size in nghttp2_stream as remote_window_size.

Fix the bug that connection-level local window is not updated
for the data is the last part of the stream. For the stream
level window may ignore this, connection-level window must
be updated. Also this change fixes the bug that connection-level
window is not updated for the ignored DATA frames.

The max length of header block is not used right now. It will
be used when header continuation is implemented.

To match the -w16 to 65535, which is HTTP/2.0 default initial window
size, decrement 1 from (1 << window_bits).