Get the correct formatPeriod off the collection.
Fix start dates following migration

The migration of dataset parameters caused an hour of timezone-ness to get added to the dates. This resulted in the first data point of the sets to return "no-data" (since I assume the monthly data is all in the database at a timestamp of midnight on the first of the month)
Test the rendering of summary time periods
Prevent stacked graphs from selecting when no model is selected

Equivalent to 3240392c769ac522dbc15eae42a71393d32e434f but for stacks as well as lines.
Fix chrome bug where border top was disappearing after sort
Add tests for stack selection on mousemove
Merge pull request #683 from alphagov/bugfix/stacked-graph-hover

Prevent stacked graphs from selecting when no model is selected
Merge pull request #681 from alphagov/bugfix/timezone-weirdness

Fix start dates following migration
Merge pull request #684 from alphagov/bugfix/sortable-tables-border

Fix chrome bug where border top was disappearing after sort
Merge pull request #680 from alphagov/bugfix/periods

Get the correct formatPeriod from the collection
Remove pinned date on carer's dashboard

We added this in to stop the graph looking funny when there wasn't
enough data.

There is now enough data.