Remove unused holeRemoverCallback function.
Add global function guard.
Add global function guard.
Add global function guard.
Merge branch 'feature/generic-datum' of github.com:SolarNetwork/solarnetwork-sites into feature/generic-datum

* 'feature/generic-datum' of github.com:SolarNetwork/solarnetwork-sites:
  Add drawAnnotationsCallback function invoked each time the chart draws, to give apps chance to overlay data onto chart. Expose some helper methods to aid that process: scaleDate() and scaleValue() to translate data into chart pixels, and stash() and stashedDate() for associating annotation data with the chart.
  Allow raw datum query, i.e. without any aggregate parameter.
Provide way to copy properties from neighbor layer data when inserting dummy values for time normalization.
In strict mode, can't test for 'sn' gobal.
Make setup function replaceable (i.e. for subclasses).
Remove unused JS.
Remove unused code.
Remove unused groupData variable.
Make setup() configurable.
Expose computeUnitsY for subclasses.
Update to generic datum API.