Tweaked menu logic
Tweaked menu logic

ref #3
Currently works when required metadata is available for sorting pages
- Issue: cannot include menu item unless a page exists for it in the
  site, i.e. no external links in the menu.

osuosl/dougfir-pelican-theme,osuosl/dougfir-pelican-theme,osuosl/dougfir-pelican-theme,osuosl/dougfir-pelican-theme