add topic sorting & js to support it

app/templates/common/icons.html

@@ -25,3 +25,7 @@
 {%- macro icn_stickied(width=16) -%}
 <img src="/static/icons/sticky.svg" title="Stickied" alt="paper held by pushpin" style="width: {{width}}px;">
 {%- endmacro -%}
+
+{%- macro icn_dragger(width=24) -%}
+<img src="/static/icons/dragger.svg" style="width: {{width}}px;">
+{%- endmacro -%}

app/templates/common/macros.html

@@ -1,4 +1,8 @@
-{%- from 'common/icons.html' import icn_info, icn_warn, icn_error, icn_bookmark, icn_megaphone -%}
+{%- from 'common/icons.html' import icn_info, icn_warn, icn_error, icn_bookmark, icn_megaphone, icn_dragger -%}
+
+{% macro dict_to_attr(attrs) -%}
+  {%- for key, value in attrs.items() if value is not none -%}{{' '}}{{key}}="{{value}}"{%- endfor -%}
+{%- endmacro %}
 
 {% macro timestamp(unix_ts) -%}
 <time datetime="{{ unix_ts | iso8601 }}">{{ unix_ts | ts_datetime('%Y-%m-%d %H:%M')}} <abbr title="Server Time">ST</abbr></time>
@@ -253,3 +257,18 @@
 </div>
 {%- endif -%}
 {%- endmacro %}
+
+{% macro sortable_list(attr=none) -%}
+<ol class="sortable-list plank even no-shadow minimal tertiary-bg" {% if attr %}{{ dict_to_attr(attr) }}{% endif %}>
+  {%- if caller -%}
+  {{ caller() }}
+  {%- endif -%}
+</ol>
+{%- endmacro %}
+
+{% macro sortable_list_item(key, immovable=false, attr=none) -%}
+<li class="sortable-item{{ ' immovable' if immovable else '' }} plank even no-shadow {{'tertiary-bg' if immovable else ''}}" data-sortable-list-key="{{key}}" {% if attr %}{{ dict_to_attr(attr) }}{% endif %}>
+  <span class="dragger plank minimal even no-shadow tertiary-bg" draggable="{{ 'true' if not immovable else 'false' }}">{{ icn_dragger() }}</span>
+  <div class="sortable-item-inner">{{ caller() }}</div>
+</li>
+{%- endmacro %}