Fixed units of delay time in limit_req log
Merge remote-tracking branch 'alibaba/master'
Merge pull request #554 from yzprofile/master

Fixed units of delay time in limit_req log
tengine 2.1.0 for release
bugfixed: syslog crashed when used in error_log within 'http' block
Merge pull request #557 from cfsego/syslog_bugfix

bugfixed: syslog crashed when used in error_log within 'http' block
updated README
Merge pull request #558 from cfsego/tengine-2.1.0u

updated README
updated release date
Merge pull request #559 from cfsego/tengine-2.1.0u

updated release date
Update conf:support assign the linker from env

if use cpp in thirdparty module, can configure usage:  LINK=g++ ./configure ....
if config with NGX_DEBUG, log with location(file, line) info
add options to set gcc
fix log bug
update tengine
:wMerge branch 'update_from_nginx2.1'