Merge branch 'erasure-intervals' of gitlab.doc.ic.ac.uk:sweng-group-15/drawing-app into erasure-intervals

My original intention for canvas.js was to receive all such data as
parameters per function call so it reflects room.js. What's confusing is
that it already is! It's been storing and exporting these properties and
then getting them back as arguments, as silly as that sounds.

Also rename some CI jobs

Also:
- Interpolate with curveBasis instead of curveLinear
- Increase the default stroke radius to 5 from 1

Fixes #48

Radius smoothing now difference relative to the max-of-2 radiii instead of absolute values.