Improve performance of report page:  Eager load interactive_items in Page. [#66528200]

https://www.pivotaltracker.com/story/show/66528200
Improve performance of report page: Simple iterate for Q.Number:  [#66528200]

(fewer partials too)
https://www.pivotaltracker.com/story/show/66528200
Improve performance of report page:  AnswerFinder preloads answers :  [#66528200]

Uses local hash lookup to find answers instead of n+1 SQL queries.

https://www.pivotaltracker.com/story/show/66528200