add validation and roll back feature
1. add large file seg_head validation check
2. roll back write when write failed or client abort
Merge pull request #254 from zhcn381/upstream

add validation and roll back feature
allow to intercept responses with status 300.
Merge pull request #255 from hnlq715/master

Upstream: allow to intercept responses with status 300.
add abi compatibility detective.
update proxy_bind to support variable
update proxy_bind to support variable
The "fastcgi_bind", "uwsgi_bind", "scgi_bind" and "memcached_bind" directives are now inherited; inherited value can be reset by the "off" parameter.  Duplicate directives are now detected.  Parameter value can now contain variables.
Merge pull request #257 from jinglong/bind

update proxy_bind to support variable
bumped version to 1.5.0
Merge pull request #259 from zhuzhaoyuan/bump-version-1.5.0

bumped version to 1.5.0
added TENGINE macro as "Tengine"
adde a member 'server_tag_header' in ngx_http_core_loc_conf_t to replace 'server_tag'
now the 'server_tokens' and 'server_tag' directives can change the server banner in a default error page.
added test cases
reverted version to 1.5.0
Merge pull request #264 from zhuzhaoyuan/suppress-server-banner

Suppress server banner in error pages
fixed coding style
fixed coding style
Merge pull request #265 from zhuzhaoyuan/fix-coding-style-1.5.0

fixed coding style