Split the upcoming graphs into another dashboard
Work in progress

- Will finish off on Monday.
Data retreival code for the burndown graph statistics

- Get the dates and numbers from the Google spreadsheet.
- Parse all of those into an array of hashes, with separate ones for
  whether or not they're expected training numbers or actual training
  numbers.
Display the data as a graph on the widget, with X and Y axes

- This involved converting the date from the spreadsheet mm/dd/yyyy
  to yyyy-mm-dd and then converting that to epoch time for it to be
  useable by the dashboard framework.
Edit the CSS to make the graph lines slightly thicker
Add a title to the graph widget and make it display at the top
Merge pull request #8 from alphagov/burndown_training_chart

Add burndown training graph as a widget to the second dashboard