Update ParseLogInterceptor to handle gzip stream

[wangmengyan95]

1. Update ParseLogInterceptor to handle GZIP response body stream
2. Decouple ProxyInputStream (Split the proxy logic and log response logic)
3. Clean ParseHttpRequest and ParseHttpResponse
4. Add test

[grantland]

Should we change this to:

public T addHeaders(Map<String, String> headers) {
  this.headers.addAll(headers);
  return self();
}

Leaving it as setHeaders where it can clear all old values seem like it could be confusing.

[wangmengyan95]

kk

[grantland]

You can get around the problem with final and try/catch by using a local var in the constructor and setting the instance vars after the try/catch.

[grantland]

Last nit, just squash and LGTM

[facebook-github-bot]

@wangmengyan95 updated the pull request.