Add support for simple social sharing links to posts

_layouts/post.html

@@ -30,6 +30,14 @@
         {% if page.modified %}<span class="entry-date date modified"><time datetime="{{ page.modified }}" itemprop="dateModified"><i class="icon-pencil"></i> {{ page.modified | date: "%B %d, %Y" }}</time></span>{% endif %}
         {% if site.disqus_shortname and page.comments %}<span class="entry-comments"><i class="icon-comment-alt"></i> <a href="#disqus_thread">Comment</a></span>{% endif %}
         <span><a href="{{ site.url }}{{ page.url }}" rel="bookmark" title="{{ page.title }}" itemprop="url"><i class="icon-link"></i> Permalink</a></span>
+        {% if page.share %}
+        <span class="social-share-facebook">
+            <a href="https://www.facebook.com/sharer/sharer.php?u={{ site.url }}{{ page.url }}" title="Share on Facebook" itemprop="Facebook"><i class="icon-facebook-sign"></i> Like</a></span>
+        <span class="social-share-twitter">
+            <a href="https://twitter.com/intent/tweet?text={{ site.url }}{{ page.url }}" title="Share on Twitter" itemprop="Twitter"><i class="icon-twitter-sign"></i> Tweet</a></span>
+        <span class="social-share-googleplus">
+            <a href="https://plus.google.com/share?url={{ site.url }}{{ page.url }}" title="Share on Google Plus" itemprop="GooglePlus"><i class="icon-google-plus-sign"></i> +1</a></span>
+            <!-- /.social-share -->{% endif %}
       </footer>
       <div class="entry-content" itemprop="description">
         {{ content }}

_posts/2011-03-10-sample-post.md

@@ -9,7 +9,8 @@ image:
   feature: so-simple-sample-image-1.jpg
   credit: Michael Rose
   creditlink: http://mademistakes.com
-comments: true  
+comments: true
+share: true
 ---
 
 Below is just about everything you'll need to style in the theme. Check the source code to see the many embedded elements within paragraphs.

_posts/2012-05-22-readability-post.md

@@ -8,7 +8,8 @@ image:
   feature: so-simple-sample-image-2.jpg
   credit: Michael Rose
   creditlink: http://mademistakes.com
-comments: true  
+comments: true
+share: true
 ---
 
 Portland in shoreditch Vice, labore typewriter pariatur hoodie fap sartorial Austin. Pinterest literally occupy Schlitz forage. Odio ad blue bottle vinyl, 90's narwhal commodo bitters pour-over nostrud. Ugh est hashtag in, fingerstache adipisicing laboris esse Pinterest shabby chic Portland. Shoreditch bicycle rights anim, flexitarian laboris put a bird on it vinyl cupidatat narwhal. Hashtag artisan skateboard, flannel Bushwick nesciunt salvia aute fixie do plaid post-ironic dolor McSweeney's. Cliche pour-over chambray nulla four loko skateboard sapiente hashtag.

_posts/2013-05-22-sample-post-images.md

@@ -4,7 +4,8 @@ title: "A Post with Images"
 description: "Examples and code for displaying images in posts."
 category: articles
 tags: [sample post, images, test]
-comments: true  
+comments: true
+share: true
 ---
 
 Here are some examples of what a post with images might look like. If you want to display two or three images next to each other responsively use `figure` with the appropriate `class`. Each instance of `figure` is auto-numbered and displayed in the caption.

_posts/2013-05-23-readability-feature-post.md

@@ -9,7 +9,8 @@ image:
   feature: so-simple-sample-image-3.jpg
   credit: Michael Rose
   creditlink: http://mademistakes.com
-comments: true  
+comments: true
+share: true
 ---
 
 This is a sample post with a large feature image[^1] up top and tons of text. Odio ad blue bottle vinyl, 90's narwhal commodo bitters pour-over nostrud. Ugh est hashtag in, fingerstache adipisicing laboris esse Pinterest shabby chic Portland. Shoreditch bicycle rights anim, flexitarian laboris put a bird on it vinyl cupidatat narwhal. Hashtag artisan skateboard, flannel Bushwick nesciunt salvia aute fixie do plaid post-ironic dolor McSweeney's. Cliche pour-over chambray nulla four loko skateboard sapiente hashtag.

_posts/2013-06-25-video-post.md

@@ -5,6 +5,7 @@ description: "Custom written post descriptions are the way to go... if you're no
 category: articles
 tags: [sample post, video]
 comments: true
+share: true
 ---
 
 <iframe width="560" height="315" src="http://www.youtube.com/embed/SqYiglufb8Y" frameborder="0"> </iframe>

_posts/2013-08-16-code-highlighting-post.md

@@ -8,7 +8,8 @@ image:
   feature: so-simple-sample-image-5.jpg
   credit: Michael Rose
   creditlink: http://mademistakes.com
-comments: true  
+comments: true
+share: true
 ---
 
 Syntax highlighting is a feature that displays source code, in different colors and fonts according to the category of terms. This feature facilitates writing in a structured language such as a programming language or a markup language as both structures and syntax errors are visually distinct. Highlighting does not affect the meaning of the text itself; it is intended only for human readers.[^1]

theme-setup.md

@@ -231,6 +231,14 @@ Not sure if this only effects Kramdown or if it's an issue with Markdown in gene
 <iframe width="560" height="315" src="http://www.youtube.com/embed/PWf4WUoMXwg" frameborder="0"> </iframe>
 {% endhighlight %}
 
+#### Social Share Links
+
+To enable Facebook, Twitter, and Google+ share links on a post or page, add the following to its front matter:
+
+{% highlight yaml %}
+share: true
+{% endhighlight %}
+
 #### Twitter Cards
 
 Twitter cards make it possible to attach images and post summaries to Tweets that link to your content. Summary Card meta tags have been added to `head.html` to support this, you just need to [validate and apply your domain](https://dev.twitter.com/docs/cards) to turn it on.