Working greying out of not selected more and changed bolded line colour

needs cleaning, needs unselect logic and tests
Remove comments and select group on stack hover
move sibling index to correct scope, select correct stack

as 0 is top of y not bottom, how to get max y for sibling selection
point?
wooh! working 0 on y
Same colours on both point selection indicators
remove logs and colour
fix post rebase
lint
Final bit of styling, hover and fix tests
remove logs and comments
broke it
fix for encompassing on graphs other than stack
remove final logs
Merge pull request #132 from alphagov/stacked-graph-improvements2

Stacked graph improvements2
Merge branch 'master' into stacked_graph_improvements
remove uneccessary line
Labels working
some refactoring and start on tests
Tests for stacked graph improvements, ehem...
tests for tooltip, not quite centered...