Adding d3 to the global.
Fixed many linting issues in line.js
Fixed linting errors in grouped_timeseries.js module.
Updated the default table view to render null data as 'no data'
Updated date-functions.js to include date formatting for moment.
New json format for axis-labels for graphs.

Added wiring for this on grouped-timeseries.

Doesn't matter
Fixing lint errors in spec file.
Added new method to collection getDataByTableFormat

Added tests for new method.
Fixing lint errors from travis.
Merge pull request #215 from alphagov/feature/accessibleGraphsPartTwo

Feature/accessible graphs part two