Add optional reading time/word count indication

via PR #134 @looer

Added config variable so this doesn't show up

Show "reading time" and "word count" but only if one of the following are true:
1) A global config `params` value is set `show_reading_time = true`
 2) A section front matter value is set `show_reading_time = true`
3) A page front matter value is set `show_reading_time = true`

layouts/_default/single.html

 {{ end }}
 
 {{ define "main" }}
+  {{ $section := .Site.GetPage "section" .Section }}
   <article class="flex-l flex-wrap justify-between mw8 center ph3 ph0-l">
 
     <header class="mt4 w-100">
       {{/* Hugo uses Go's date formatting is set by example. Here are two formats */}}
       <time class="f6 mv4 dib tracked" datetime="{{ .Date.Format "2006-01-02T15:04:05Z07:00" }}">
         {{- .Date.Format "January 2, 2006" -}}
-      </time>
+      </time>      
+      {{/*  
+          Show "reading time" and "word count" but only if one of the following are true:
+          1) A global config `params` value is set `show_reading_time = true`
+          2) A section front matter value is set `show_reading_time = true`
+          3) A page front matter value is set `show_reading_time = true`
+        */}}
+      {{ if (or (eq (.Param "show_reading_time") true) (eq $section.Params.show_reading_time true) )}}
+        <span class="f6 mv4 dib tracked"> - {{ .ReadingTime}} minutes read</span>
+        <span class="f6 mv4 dib tracked"> - {{ .WordCount}} words</span>
+      {{ end }}
     </header>
 
     <main class="nested-copy-line-height lh-copy serif f4 nested-links nested-img mid-gray pr4-l w-two-thirds-l">