#1289 Enhance the Top Voted list

[Ahasuerus]

Create a "Top 100 Short Fiction as Voted by ISFDB Users" list. Create sublists for novellas, novelettes and short stories. Create "most controversial" lists for these title types using the following logic:

select std(rating),title_id from votes group by title_id having count(user_id)>3 order by std(rating) desc

[Ahasuerus]

Part 1 - Added a Top Short Fiction list; changed the maximum length from 100 to 500:

biblio/stats-and-tops.py
biblio/stats.py
nightly/nightly_stats.py

Installed in SVN 474 on 2019-10-26. Keeping the FR open.