Update README.md

Document usage of --quic-version

Support arm64 and arm builds

Document usage of redir://

Fix OnPushComplete logic

Should not Push the same thing again.

Fix OnPushComplete logic

Should not Push the same thing again.

Fix Travis build on MacOS

Add continuous integration and tests

Add continuous integration and tests

quic: Fix HTTP/3 Fast CONNECT behavior

SpdyProxyClientSocket uses read_callback_ for both Connect() and
Read(), and its OnIOComplete() calls read_callback_, thus its fast
connect code checks read_callback_. The code was ported to
QuicProxyClientSocket without much change.

But QuicProxyClientSocket uses a separate connect_callback_ apart from
read_callback_, and its OnIOComplete() calls connect_callback_, thus
when headers are received after Connect() it doesn't need to check
read_callback_ and should always avoid calling connect_callback_.