Ensure different lines widget type instances don't share the same colour scale
Use metric keys as color input instead of indices
Remove unnecessary whitespace
Remove unnecessary guarding being done when initialising lines widget's colors property
Merge branch 'develop' into feature/issue-42-colours-attempt-3

Conflicts:
	src/scripts/widgets/lines.js
Merge branch 'feature/issue-42-colours-attempt-3' into develop
Build