使用jcrop进行头像剪切

http://www.cnblogs.com/chenssy/archive/2013/05/18/3084985.html

http://code.ciaoca.com/jquery/jcrop/

http://blog.csdn.net/kenhins/article/details/17136815

http://terje.blog.163.com/blog/static/11924371201101311319664/

http://www.cnblogs.com/zxdBlog/p/3580361.html

http://www.oschina.net/code/snippet_218887_22896