Adds summary to archives page.
Merge branch 'new-archive-page' of https://github.com/PyHOGS/pyhogs.github.io into new-archive-page

 the commit.
cleaned up summaries for all our posts.
Merge branch 'new-archive-page' into pelican-source

* new-archive-page:
  cleaned up summaries for all our posts.
  Adds summary to archives page.