Fix Ronding Error in when using numeric Keyboard
Fix LKASSERT in Select Waypoint dialog when no Valid WayPoint.
Add MIDCENTER option for visual glide, to use also center line for positioning boxes
Do not use obstacle calculations for waypoints with an arrival altitude below 50m.
It would be inaccurate in any case, because terrain could be not accurate enough,
or most likely the waypoint declared altitude could be wrong, and the waypoint be BELOW terrain itself.
Or the waypoint position may be simply shifted by a few dozen meters from the real position, for example beyond the ridge.
We give yellow condition all the way, below 50m arrival!
Scale correctly VG windows, using correct screen range available
Merge branch 'Fix' of http://github.com/brunotl/LK8000