Fix issue:can not link to home page

Hi, Michael,
First, my English is poor.
There is a problem when I deploy hpstr on github pages, if  my **_config.yml** like this:
~~~raw
url: blog.zhibeiyou.net
~~~
Then the url on github page is like: blog.zhibeiyou.net/blog.zhibeiyou.net/my-blog/

So, my **_config.yml** is like this:
~~~raw
url: 
~~~
Everthing is seems OK. But I can't jump to home page. 

With the modify of the patch, I can jump to home page now.
Sorry for my poor English.

Herodot