Use SPDY to connect to backing services

Spotlight currently makes a lot of backing service requests over SSL. We
should see an improvement in our response times by using SPDY to connect
to each domain/port combination over SPDY, and only pay the overhead of
setting up a single TCP connection to have a conversation over TLS.

Currently, a request to render HTML might make 10 requests. Default node
settings will allow up to 5 connections to be made to a host / port
combination, so we will have the overhead of setting up 5 TLS
connections, then hopefully see connection keep alive giving a slight
benefit.

This change needs benchmarking and profiling to ensure that we’re
using SPDY correctly.

Can be traced in wireshark / tcpdump with ip.addr == 37.26.89.53 on
preview.
Add clarification to 'report a problem' form

This text is intended to try and reduce the number of tickets that
we receive which should actually be sent to the product teams rather
than to us.

Clarify that the form on this page is for dashboard problems only.
Merge pull request #866 from alphagov/report-a-problem-clarification

Add clarification to 'report a problem' form
Merge pull request #867 from alphagov/feature/spdy

Use SPDY to connect to backing services
Don't flatten the data for the applications module.
Merge pull request #868 from alphagov/bugfix/applications

Don't flatten the data for the applications module.
Revert "Merge pull request #867 from alphagov/feature/spdy"

This reverts commit 0f433e72ec1c3cf0b6e566228d94b82ee3cded57, reversing
changes made to b9bea851211423656182b6983a876f609d5cbc50.

Seeing if this is causing cheapseats failure in production.
Revert "Revert "Merge pull request #867 from alphagov/feature/spdy""

This reverts commit df5ae65ddaf10d1ff130575159092dcb6388c420.

The build still failed in our CI (but was fine in Travis?). Need to
look for a different culprit.
Update cheapseats

We would like to use the version that lets you test a single dashboard, 
since that’s quicker than waiting for them all to run when you’re
trying to diagnose an issue.
Merge pull request #869 from alphagov/bump-cheapseats

Update cheapseats