Linting fixes for completion_rate
Fixed lint errors in spec.completion.js
Pass through the graph axis labels into the collection.

This is used to render accessible graphs (tables) but could be used on the actual graphs for axis labels.
Adding formatting of graphs for completion_rate component.

Added tests.
Added axis-lables for no-realistic-dashboard

This allows us to have tables that make sense for completion_rate modules.
Merge pull request #224 from alphagov/feature/accessibleCompletionRateGraphs

Feature/accessible completion rate graphs