added accurate mortar range circle

[RasmusGodske]

I noticed that the mortar range circle is a fixed radius and does not account for height differences. So I have implemented a feature which makes it possible to show the accurate mortar range circle around the active mortar. The feature adds a toggle button within the "Map Settings" which lets the user decide themselves if they wanna use it or not.

It's worth mentioning that calculating the max ranges all around the mortar is fairly slow. It is done by splitting up the circle into smaller points and bearings and then test the max range. This gives a lot of points which is used to draw a polygon. I'm sure this could be done more efficiently.