We add a new way to access blog page. Now there are 3.
The switch now uses number to choose the way.
1 is for subdomain and 3 is for subfolder.
2 is for separated blog domain with its subfolder.
For example, mike's link is blog.xxx.xxx/mike.
Blog list page link on navbar will change by domain mode.
When using sub-directory blog, the 'blogof' not looks so good.
And, there are duplicate 'blog' characters, which making people uncomfortable.
So, for sub-directory blog, use 'blog' instead of 'blogof'.
'blog' is not as a sub folder or type anymore, use 'post' instead.
BREAKING CHANGE: Due to the conflict of 'blog' sub-directory, when go to blog post,
now should use 'blogs/{id}'; but when subdomain mode is on, you can still use 'blog'
to access these blog posts. 'blogof' is no longer used, and you need to inform users
that blog link is changed, to avoid the inaccessbility.
