Remove share buttons

About 0.19% of visitors in the past 12 months have clicked the share
buttons at all. The code is a little ugly, and it wastes a tiny bit of
space at the bottom of the page. I don't think it's really worth having.

And I think people probably print a page through the browser UI anyways.

layouts/page.html

@@ -60,10 +60,6 @@
         </div>
     {{ end }}
 
-    {{ if .Site.Params.shareButtons }}
-        {{ partial "share.html" . }}
-    {{ end }}
-
     {{ if .Params.comments }}
         <div class="comments">
             {{ partial "comments.html" . }}