Update README.md

update readme

优化..

Delete profiles_settings.xml

update new version

修改 预览图片的布局

Update README.md

Merge branch 'master' of github.com:donglua/PhotoPicker

Merge pull request donglua#14 from donglua/developer

0.2.1

Merge pull request donglua#5 from donglua/developer

完善文档和Demo