Hover state on shared tooltip

[KacperMadej]

Behaviour

Point hover state is not changing when another point is hovered.

Live demo with steps to reproduce

http://jsfiddle.net/1ohybfru/

1. Hover over the plot area, but over the columns- first will keep being in hover state.
2. Hover over a column and hover over other columns - the column will keep hover state while another column (as it should) will be in hover state.

Github code fixes this problem, but creates another:
http://jsfiddle.net/1ohybfru/1/

1. Hover from left to right within yAxis gridlines for ticks 5 and 6 - tooltip and hover state will not jump to the last column.
2. Go down around last column, but inside chart's plot area - tooltip and hover state still not on the last column.