Fix subdomain, add test, space and comment fix

Cleaning things when learning the code. 
I took it for granted that it will return [""]

发自我的 iPhone

> 在 2014年12月18日，下午9:23，astaxie <notifications@github.com> 写道：
> 
> In config/json.go:
> 
> >  }
> >  
> >  // Strings returns the []string value for a given key.
> >  func (c *JsonConfigContainer) Strings(key string) []string {
> > +	stringVal := c.String(key)
> there's no necessary to add these code. because strings.Split("",";") will retrun []string{}
> 
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