pelican-bootstrap3: refactored sidebar (#466)

This is more of a proposal for refactor of the sidebar.  Figured it
would be easier to do and discuss in a PR than it would be an
issue/ticket.

These changes can be split out if only some of the ideas are accepted.
It is mostly a lot cleanup and shuffling around to make it a bit more
consistent.

Here is a summary of the changes:

  - Moved all sidebar related from `includes/` and into
    `includes/sidebar/`.
  - Moved the following sections in `includes/sidebar.html` into
    their own files under `includes/sidebar/`:
    - _Social_ -> `includes/sidebar/social.html`
    - _Recent Posts_ -> `includes/sidebar/recent_posts.html`
    - _Categories_ -> `includes/sidebar/categories.html`
    - _Tags_ -> `includes/sidebar/tag_cloud.html`
    - _Series_ -> `includes/sidebar/series.html`
  - A whole bunch of whitespace cleanup.
  - Added the `DISABLE_SIDEBAR_TITLE_ICONS` configuration option. If
    `DISABLE_SIDEBAR_TITLE_ICONS` is set to True, none of the sidebar
    title icons will be displayed.
  - Folded in from getpelican/pelican-themes#438: Added the
    `SIDEBAR_ON_LEFT` configuration option, which moves the sidebar
    to the left side of the page.  Sidebar will continue to appear on
    the bottom of the page on smaller screens.
  - Assuming getpelican/pelican#1092 worked out:
    - Optional include of `includes/sidebar/optional_top.html` and
      `includes/sidebar/optional_bottom.html` from within
      `includes/sidebar.html`.  This would allow a user to insert
      sections into the sidebar.
    - `includes/sidebar/recent_posts.html` include articles line items
      via `includes/sidebar/article-li.html`.  This allows customization.

1 files changed, 16 insertions, 0 deletions

diff --git a/pelican-bootstrap3/templates/includes/sidebar/links.html b/pelican-bootstrap3/templates/includes/sidebar/links.html
new file mode 100644
index 0000000..179b1a3
--- /dev/null
+++ b/pelican-bootstrap3/templates/includes/sidebar/links.html
@@ -0,0 +1,16 @@
+{% if LINKS %}
+  {% from 'includes/sidebar/macros.jinja' import title %}
+
+<!-- Sidebar/Links -->
+<li class="list-group-item">
+  <h4>{{ title(_('Links'), DISABLE_SIDEBAR_TITLE_ICONS, icon='external-link-square') }}</h4>
+  <ul class="list-group" id="links">
+    {% for name, link in LINKS %}
+    <li class="list-group-item">
+      <a href="{{ link }}" target="_blank">{{ name }}</a>
+    </li>
+    {% endfor %}
+  </ul>
+</li>
+<!-- End Sidebar/Links -->
+{% endif %}