Develop some JMeter benchmark scripts to test Anonymous running.

[#64672008]
https://www.pivotaltracker.com/story/show/64672008
Improved benchmark script, includes multiple choice, and timings.
Latest version of the user load testing scripts as per [#64672008]

https://www.pivotaltracker.com/story/show/64672008
Fix some N+1 queries on the home page.
Fix some N+1 queries on the index pages for activities and sequences.
Add 'updated_at' index to sequences and activities to speed up index.
Add 'updated_at' index to sequences and activities to speed up index.
Faster selection of runs.  Was lowing down index pages [#66528876]

https://www.pivotaltracker.com/story/show/66528876
Added benchmark deploy target for running JMeter against.
Start of Spec tests for portal publication work from a few weeks ago.
Use counter to return active_runs count, addresses [#66528876]

https://www.pivotaltracker.com/story/show/66528876
Remove run joins now that the active_runs uses counter.

Addresses [#66528876]

https://www.pivotaltracker.com/story/show/66528876
Make question prompts bold. Works around font-family helvetica-medium.
Speed up reports page, by removing strip_tags and redundant no_itals.
Updates to the benchmarking script.
New NatGeo Climate background image as per:  [#66528876]

https://www.pivotaltracker.com/story/show/66528876
A stretchy, non-tiling (covering) background image: [#64495486]

https://www.pivotaltracker.com/story/show/64495486
Full-width layout: 2 embeddables per line, left-right, top-bottom order

[#64495668]

https://www.pivotaltracker.com/story/show/64495668