image_filter support crop_keepx/crop_keepy

crop_keepx reduces the image by width and crops extraneous edges by height.
crop_keepy reduces the image by height and crops extraneous edges by width.
Bugfixed: rewrite directive do not use ngx_http_named_location
Merge pull request #456 from cfsego/tengine_2.0.3

Tengine 2.0.3
Merge remote-tracking branch 'alibaba/master'
Merge pull request #455 from yzprofile/master

Bugfixed: rewrite directive do not use ngx_http_named_location
Merge pull request #448 from Lax/feature/image_filter_crop_keep

image_filter支持crop_keepx/crop_keepy
consistent_hash和session_sticky模块支持ssl session保持
type error
Merge pull request #463 from dinic/ssl_session

consistent_hash和session_sticky模块支持ssl session保持
Add .travis.yml for travis-ci.org testing

http://docs.travis-ci.com/user/getting-started/

If we link travis-ci.org to https://github.com/alibaba/tengine,
we can perform continuous testing against new commits to ensure
they do not break the build. travis-ci.org is a free service.

This commit provides an appropriate configuration file to tell
travis-ci.org about tengine and how we build it from source.
Merge pull request #466 from Jamyn/master

Add .travis.yml for travis-ci.org testing