Add "el>90 checkbox" to allow for elevations > 90 deg (default yes)

[varenius]

Good to take shortest path, el >90deg if needed, but in some cases (e.g. pointing check measurements) we don't want this since it complicates life. Would be nice with a checkbox on the Advanced/Advanced tab of the control GUI for "Allow alt > 90 deg" which is checked by default. Should have explanatory tooltip and translation.