Use color from datadef as an override

- Use color from datadef as an override.
Add support for deviation value in LegendView

- Calculate deviation value of a line based on points of another
  dataset.

- Modify legend parsing.
Add checks and comments

- Check datadef for null value before fetching color for
  dataRepresentation.

- Add comment on parsing of data node in the graph pane.
Set color in datadef

- Set color in datadef to support legend in old activities.

- Revert accidental removal of code from 'setupGraph'.
Fix point population code of 'dataref'

- Fix point population code of 'dataref'.
Fix datadef removal bug and code cleanup

- Fix datadef removal bug on sort of datadef list for graph pane.

- Code cleanup in 'unordered_data_points.js'.
Update legend view

- Update legend's position on next step.

- Add and remove observer within legend on datadefs' 'deviationValue'
  when appropriate.
Add "deviationValue" operator

- Add "deviationValue" operator.
Add sample activity file to 'activity_json'

- Add 'best-fit-sequence.js' file for type "Best Fit Sequence".
Fix bug of legend's position

- Fix bug of legend's position for multiple pages on page change.
Fix bug when datadef is undefined

- Fix bug when datadef is undefined.
Update calculation of deviation value

- Update calculation of deviation value based on vertical distance
  rather than perpendicular distance of a point to the line.
Update calculation of deviation value

- Update calculation of deviation value by taking square root of it.
Fix typo error

- Fix typo error
Update sample activity file

- Update sample activity file for best fit sequence.
Modify calculation for deviation

- Use sum of squares for calculation of deviation value.
Update sample activity file

- Update sample activity file for best fit sequence.
IE can be strict abt field vs methods in applets

[#37044931]
Refactor code and add appropriate comment

- Refactor code and add appropriate comment.
Cleanup and add comment

- Cleanup and add comment.