Support for left and right

If the turn being made is a left or right turn, and turn:lanes is present, then the lanes for the turn will be displayed, and only the lane that takes a left or right turn will be highlighted.

In addition, in the US (at least), the ability to take a right turn from the right-most lane is generally implied and not explicitly indicated on signage. Therefore, `turn:lanes` might not contain the right turn. The problem is that if a right turn is being taken, but `turn:lanes` doesn't have a lane where the right turn is indicated, then none of the lanes will be highlighted.

This fix checks to see if a right turn is being taken and that the right-most lane has some right turn indication. The same (but flipped directions) applies to the left turn for countries driving on the left side.