Fixes #20 and #13

[hdurand]

It does the following:

• Shows scores (captured in #20):
  • publishers scores in the publishers table:
  • score = sum of all publishers scores from results / number of scores
  • sources scores in the sources table:
  • score = latest score from results (based on timestamp)
  • files with score < 10 are invalid
• Shows performance over time on all pages with a line chart (captured in #20):
  • lines series for valid and invalid percentages:
  • by month for the last 12 months (based on timestamp from results)
• Sorts tables (captured in #13):
  • publishers table:
  • by score (descending) and by name (ascending)
  • sources table:
  • by score (descending), date (descending, based on timestamp from results), publisher id (ascending), name (ascending)
  • sorting also by publisher id and name made sense to me when looking at the tables but let me know if I should remove that
• Shows timestamp from results in sources table (instead of timestamp from sources)
• Switches timely % to invalid % in the overview section on the main page and on the publisher page (closes #23?)
• Removes sub-publishers count from the overview section on the publisher page

[pwalsh]

Hi @hdurand ! I've reviewed all the code - looks great! So glad to see you've dived into the code so well!

[hdurand]

Great! :)