Blog enhancements (#80)

* Small CSS adjustments.

* Blog adjustments.

* Add support for Prism in the blog

lib/core/BlogPostLayout.js

@@ -15,6 +15,40 @@ const Site = require("./Site.js");
 
 // used for entire blog posts, i.e., each written blog article with sidebar with site header/footer
 class BlogPostLayout extends React.Component {
+
+  renderSocialButtons() {
+    const post = this.props.metadata;
+    
+    const fbLike = this.props.config.facebookAppId ? 
+    <div
+      className="fb-like"
+      data-layout="standard"
+      data-share="true"
+      data-width="225"
+      data-show-faces="false">
+    </div>
+    : null;
+
+    const twitterShare = this.props.config.twitter ?
+    <a href="https://twitter.com/share" className="twitter-share-button" data-text={post.title} data-url={this.props.config.url + this.props.config.baseUrl + "blog/" + post.path} data-related={this.props.config.twitter} data-via={post.authorTwitter} data-show-count="false">Tweet</a>
+    : null;
+
+    if (!fbLike && !twitterShare) {
+      return;
+    }
+
+    return (
+      <div>
+        <aside className="entry-share">
+          <div className="social-buttons">
+            {fbLike}
+            {twitterShare}
+          </div>
+        </aside>
+      </div>
+    );
+  }
+
   render() {
     return (
       <Site
@@ -39,6 +73,7 @@ class BlogPostLayout extends React.Component {
                 language={"en"}
                 config={this.props.config}
               />
+              {this.renderSocialButtons()}
             </div>
             <div className="blog-recent">
               <a