Compass to show camera Slope and Azimuth

[stheid]

Hey guys, i dont want to flood the repo with issues, but i think this is also relatively simple to implement and of high value

Together with sonnenverlauf it would be really helpful to have a way to print the camera heading and azimuth to understand shading from other buildings.

My suggestion (if you are inclined to implement it ^^) would be to have the corner tooltip say something like

Kamera:

• Neigung
• Azimuth
  Mauszeiger:
• Neigung
• Azimuth

Ideally this would be combined with an option for a orthogonal projection camera of course, but i assume thats much much harder to implement.

If there is a reasonably simple way for me to help, i would be also interested to compute the horizon file (PVGIS) for the position from the building data, but i assume thats not trivial.