allow base_url and url with absolute_url

[kakila]

Hi,
in plenty of places you use {{site.url}} when you want to give a absolute link to folders and files, this doesn't play well when base_url and url are used together. You can replace all of these instances with absolute_url, e.g. the current {site.url}/images/logo.png is replaced with {{ "images/logo.png" | absolute_url }}.

I will share a blog soon where I use you modified theme, so you can check all the changes.