Replace the ray-to-dem intersection algorithm with the secant method

merge

Save with debug info removed

Add code with no debug info

Wipe more debug logic

Tweak some comments

Punctuation

Hardening the logic for intersecting ray with DEM

DemShape: Let tolerance bet 1/1000 pixel, as that is more robust

Fix FunctionalTestsCamdev and FunctionalTestsCamrange

Fix FunctionalTestsCampt and FunctionalTestsCamstats