Fix indentation
Simplify code using `googleplus_user` as author

`else` makes `googleplus_user` not empty even if `site.googleplus_user`
is empty.
Use HTTPS when on HTTPS site

See ec1fbccd64fc429b138369f93c1236a8dedc7ce6.
Join MathJax script lines
Use double quotes in HTML
Merge pull request #52 from yous/patch-mathjax

Use HTTPS when on HTTPS site
Merge pull request #51 from yous/patch-googleplus-user

Simplify code using `googleplus_user` as author