github常见操作和常见错误!错误提示:fatal: remote origin already exists.
http://blog.csdn.net/god_wot/article/details/10522405
Why call git branch --unset-upstream to fixup?
为什么叫分支——取消上游修正?
http://www.4byte.cn/question/52687/why-call-git-branch-unset-upstream-to-fixup.html
**Git入门指南十一:Git branch 分支与合并分支******
http://blog.csdn.net/wirelessqa/article/details/20153689