Publication image zoom (alshedivat#1554)

Fixes alshedivat#1552

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Signed-off-by: George Araujo <george.gcac@gmail.com>

Author: george-gca

_layouts/bib.html

@@ -5,12 +5,13 @@
         <div class="col-sm-2 {% if entry.preview %}preview{% else %}abbr{% endif %}">
         {%- if entry.preview -%}
           {% if entry.preview contains '://' -%}
-          <img class="preview z-depth-1 rounded" src="{{ entry.preview }}">
+          <img data-zoomable class="preview z-depth-1 rounded" src="{{ entry.preview }}">
           {%- else -%}
             {%- assign entry_path = entry.preview | prepend: '/assets/img/publication_preview/' -%}
             {% include figure.html
             path=entry_path
             class="preview z-depth-1 rounded"
+            zoomable=true
             alt=entry.preview -%}
           {%- endif -%}
         {%- elsif entry.abbr -%}