Abs link patch (#506)

* Fix absolute URL generation

url and baseurl config for this theme deviates from jekyll standard,
and that results in double inclusion of project path
if this theme is used as project page.

Switching to Jekyll accepted url usage so that
absolute_url filter works.

* Alternate links need to be aboslute

* mention url and baseurl only need to be modified in local dev

* Update readme on new url/baseurl setting changes

tags.html

@@ -23,7 +23,7 @@ title: 'Tag Index'
     <div class="post-list">
         {%- for post in site.tags[tag] -%}
             <div class="tag-entry">
-                <a href="{{- site.url -}}{{- post.url -}}">{{- post.title -}}</a>
+                <a href="{{ post.url | relative_url }}">{{- post.title -}}</a>
                 <div class="entry-date">
                     <time datetime="{{- post.date | date_to_xmlschema -}}">{{- post.date | date: "%B %d, %Y" -}}</time>
                 </div>