Replacing deprecated function call with now preferred version (#39)

Using the old call was producing the following Warning:

WARNING: Page's Now is deprecated and will be removed in a future
release. Use now (the template func).

layouts/partials/sidebar.html

       {{end}}
     </ul>
 
-    <p>{{ with .Site.Params.copyright }}{{.}}{{ else }}&copy; {{.Now.Format "2006"}}. All rights reserved. {{end}}</p>
+    <p>{{ with .Site.Params.copyright }}{{.}}{{ else }}&copy; {{ now.Format "2006"}}. All rights reserved. {{end}}</p>
   </div>
 </div>