Separate mixins and fonts from base.less (#821).

Allows for more granularity in including floodlight styles.
New style and content for embeddable widget (#821).

Currently somewhat responsive; further refinement required.
Merge branch '741-embed_widget' into 821-embed-widget-template
List-only view in widget (#821).

- Refactor story_widget.html into three files: widget_base.html,
  widget_story_section.html, and widget_list_section.html.
- CSS, view, and template logic to make things work.
Refactor widget template structure (#821).

- Refactor widget structure into base file with a single content
  block.
- Additionally, list and story markup are separated into their own
  files to avoid repetition.
- Javascript to attach handlers to anchor tags to open links in new
  window.
- CSS, view, and template logic to make things work.
Enable compression on inline widget script (#821).
Paramaterize widget width; fix JS typo (#821).

- Widget width can be set via data-width attribute (parallel to
  data-height).
- Fix typo in definition of trim polyfill (caused widget to
  fail in IE8).
Widget layout improvements; IE8 compat (#821).

- Use background image and background-size techniques to layout
  images in browsers that support background-size.
- Tweaks to breakpoints and responsive design.
- Widget basically working in IE8. Much of this commit involves
  changes to support IE8.
- Open issues:
  - Some more tweaking of sizing and layout would make the widget
    look better in some sizes across all browsers.
  - Media queries do NOT work in IE8 when widget is in iframe, even
    with css3-mediaqueries.js. This is the case when CSS is inline
    as well as when linked via file. Respond.js *may* work where
    css3-mediaqueries.js does not.
  - IE8 detection for CSS-based fixes in the LESS file is done via
    modernizr's no-backgroundsize class on html. This is not really
    appropriate use of the class. Conditional inclusion of fixup CSS
    files is probably more appropriate, but I'm not sure if the
    overhead of that is worthwhile.
Better header/footer CSS; footer links (#821).

- Use table/table-cell technique to vertically align header and
  footer items even when multi-line.
- Related item links in footer are interleaved between projects
  and organizations, trailing comma problem fixed.
- Don't limit vertical size of images within list items (list items
  will clip).
Merge branch '821-embed-widget-template' into 741-embed_widget
Merge pull request #866 from patternleaf/741-embed_widget

Merge in updates to embed widget styling by @patternleaf