Minor proofreading corrections to Hugo docs

- Add backticks and commas where necessary
- Remove some trailing whitespace
- Add front matter example in TOML
- Fix typo in one of the tags in Showcase
- Add 多说 (Duoshuo) as an alternative to Disqus
- Use internal links (i.e. without gohugo.io) where possible
- Use a colon to set off an example
- Change "it's" to "its" where appropriate
- Use typographical (i.e. curly) apostrophe on the front page
  where appropriate
- Capitalize "Github" as "GitHub"

docs/layouts/index.html

@@ -31,7 +31,7 @@
         <a href="/overview/introduction" class="btn btn-primary btn-lg">Docs <i class="icon-idea"></i></a>
         <a href="#action" class="btn btn-success btn-lg">Install <i class="icon-arrow-down"></i></a>
         <a href="http://discuss.gohugo.io" class="btn btn-info btn-lg">Community <i class="icon-talking"></i></a>
-        <a href="https://github.com/spf13/hugo" class="btn btn-dark btn-lg">Github <i class="icon-circlestar"></i></a>
+        <a href="https://github.com/spf13/hugo" class="btn btn-dark btn-lg">GitHub <i class="icon-circlestar"></i></a>
         </div>
       </div>
     </div>
@@ -49,7 +49,7 @@
                     Introducing Hugo, a new idea around making website creation simple again.
                     Hugo flexibly works with many formats and is ideal for
                     blogs, docs, portfolios and much more.
-                    Hugo&#39;s speed fosters
+                    Hugo’s speed fosters
                     creativity and makes building a website fun again.
                 </p>
               </div>
@@ -68,9 +68,9 @@
                   <i class="point-icon icon-windows8"></i>
                 <h2>Run Anywhere</h2>
                 <p class="lead">
-                Hugo is quite possibly the easiest to install software you&#39;ve ever used,
-                simply download and run. <b>Hugo doesn&#39;t depend on administrative privileges, databases, runtimes, interpreters
-                    or external libraries</b>. Sites built with Hugo can be deployed on S3, Github Pages, Dropbox or any web host.
+                Hugo is quite possibly the easiest to install software you’ve ever used,
+                simply download and run. <b>Hugo doesn’t depend on administrative privileges, databases, runtimes, interpreters
+                    or external libraries</b>. Sites built with Hugo can be deployed on S3, GitHub Pages, Dropbox or any web host.
                 </p>
               </div>
             </div>
@@ -89,7 +89,7 @@
 
                 Hugo is written for speed and performance. Great care has been
                 taken to ensure that Hugo build time is as short as possible.
-                We're talking milliseconds to build your entire site for most setups.
+                We’re talking milliseconds to build your entire site for most setups.
 
                 </p>
               </div>
@@ -147,7 +147,7 @@
                       <div class="item"> <blockquote><p>I love Hugo! My site is generated with it now http://rjrbt.io </p>&mdash; Nathan Toups (@rojoroboto) <a href="https://twitter.com/rojoroboto/status/423439915620106242">January 15, 2014</a></blockquote> </div>
                       <div class="item"> <blockquote><p>this is AWESOME. a single little executable and so fast.</p>&mdash; Luke Holder (@lukeholder) <a href="https://twitter.com/lukeholder/status/430352287936946176">February 3, 2014</a></blockquote> </div>
                       <div class="item"> <blockquote><p>OK, so in today's speed battle of static site generators, @spf13's hugo is kicking everyone's ass, by miles.</p>&mdash; Kieran Healy (@kjhealy) <a href="https://twitter.com/kjhealy/status/437349384809115648">February 22, 2014</a></blockquote> </div>
-                      <div class="item"> <blockquote><p>I think I'm going to level up and try @spf13 's Hugo for my next project.</p>Dave Cheney (@davecheney ) <a href="https://twitter.com/davecheney/status/448036906740097024">March 24, 2014</a></blockquote> </div>
+                      <div class="item"> <blockquote><p>I think I'm going to level up and try @spf13&nbsp;'s Hugo for my next project.</p>Dave Cheney (@davecheney ) <a href="https://twitter.com/davecheney/status/448036906740097024">March 24, 2014</a></blockquote> </div>
                       <div class="item"> <blockquote><p>I just fell in love with #hugo, a static site/blog engine written by @spf13 in #golang  + stellar docs</p>&mdash; Dave Cottlehuber (@dch__) <a href="https://twitter.com/dch__/status/460158115498176512">April 26, 2014</a></blockquote> </div>
                       <div class="item"> <blockquote><p>Another site generated with Hugo here! I'm getting in love with it. </p>&mdash; Javier Segura (@jsegura) <a href="https://twitter.com/jsegura/status/465978434154659841">May 12, 2014</a></blockquote> </div>
                       <div class="item"> <blockquote><p>One more satisfied #Hugo blogger. Thanks @spf13 and friends!</p>&mdash; Michael Whatcott (@mdwhatcott) <a href="https://twitter.com/mdwhatcott/status/469980686531571712">May 23, 2014</a></blockquote> </div>

docs/layouts/section/showcase.html

@@ -7,6 +7,6 @@
         {{ end }}
         </div>
   <br><br>
-  If you want to be added to this page please send a <a href="https://github.com/spf13/hugo/pulls">pull request</a>.
+  If you want to be added to this page, please send a <a href="https://github.com/spf13/hugo/pulls">pull request</a>.
 
 {{ partial "footer.html" . }}