add deb packaging config
SPDY: fix bug that server_tag directive can not work
docs: added historical information about directive "check_keepalive_requests"
merge changes between nginx 1.4.6 and 1.4.7

 Details are as following:

 *) Security: a heap memory buffer overflow might occur in a worker
    process while handling a specially crafted request by
    ngx_http_spdy_module, potentially resulting in arbitrary code
    execution (CVE-2014-0133).
    Thanks to Lucas Molas, researcher at Programa STIC, Fundación Dr.
    Manuel Sadosky, Buenos Aires, Argentina.

 Changeset: http://hg.nginx.org/nginx/rev/e7f7d30196e3

 Note that this bug has been fixed in Tengine-2.0.2.

 *) Bugfix: in the "fastcgi_next_upstream" directive.
    Thanks to Lucas Molas.

 Changeset: http://hg.nginx.org/nginx/rev/b246018860a2
Merge pull request #438 from chobits/nginx-update-1.4.7

merge changes between nginx 1.4.6 and 1.4.7
Merge pull request #437 from chobits/doc_bugfix

docs: added historical information about directive "check_keepalive_requests"
Merge pull request #436 from chobits/spdy_bugfix

SPDY: fix bug that server_tag directive can not work
调整session_sticky模块的顺序
Merge pull request #441 from dinic/session_sticky_dso

调整session_sticky模块的顺序
bugfix: do not copy '.so' to destination directory.
Merge pull request #442 from cfsego/dso_bugfix1

bugfix: do not copy '.so' to destination directory.
Merge pull request #418 from betetrpm/master

add debian/ubuntu packagine config
Update README.md

- break long dependency line
- defining `DEB_BUILD_OPTIONS` is like export
- `tengine_2.0.2-1_amd64.deb` is just an example
Merge pull request #443 from szepeviktor/patch-2

genius work!
I feel it now more attractive
Thank you very much
docs: more information for proxy_buffering_off directive if enabling spdy

Thanks for Arlen Stalwick's advice.

More details are available here:
 https://github.com/alibaba/tengine/issues/444