added the feature of request_no_buffering for http and fastcgi proxy
added English docs for request_non_buffering
added more test cases for request_non_buffering
fixed the code, remove some useless expressions.

Thanks to weiyue
Merge remote-tracking branch 'taobao/master' into request_no_buffering
remove the timer when the no buffer request body read handler returns NGX_OK
Merge branch 'develop' into request_no_buffering
fixed the wrong finalized function for upstream
Merge branch 'develop' into request_no_buffering
added socket nodelay for non buffered request when sending data to upstream
recover the read event
Merge branch 'develop' into jst

Conflicts:
	auto/sources
Merge branch 'request_no_buffering' into jst
fixed the segment fault with ipstat_module
bugfix: ip:port pair will cause crash when the same port goes with different IPs, but does not use wild IP match.
bugfix: malformed value inheritation.
Merge remote-tracking branch 'weiyue/statistics' into jst
update testcase
Merge remote-tracking branch 'weiyue/statistics' into jst
bugfix: avg is incorrect
bugfix: avg is incorrect