Skip read-time if it's a minute or less

I don't think the read-time is adding much value on short pages. The
reader is likely able to make a better estimation how long it would
take to read.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

_includes/read_time.html

@@ -1,6 +1,4 @@
 {%- assign words = content | number_of_words -%}
-{%- if words < 360 -%}
-<p><em class="reading-time">Estimated reading time: 1 minute</em></p>
-{%- else -%}
+{%- if words >= 360 -%}
 <p><em class="reading-time">Estimated reading time: {{ words | divided_by:180 }} minutes</em></p>
 {%- endif -%}