0475: revamped waypoint signage system
closes #439
* the pyramid now shows the waypoint's direction
* each waypoint is connected to the next with a blue line
* the waypoint's direction is calculated in 3D space, meaning also takes into account the vertical direction
* both the pyramid and the line are also visible at night
* the waypoint display mode is now saved for each vehicle
Merge branch 'master' of https://github.com/Courseplay/courseplay