Add ability to fully use turn:lanes for left and right turns as well

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.
Add a right/left turn arrow on the rightmost/leftmost lane if it's not
included as per turn:lanes and a right/left turn is being taken.