Add Conical ESS Turnpoint for PG optimized Task.
fix Conical ESS Task point drawing
avoid wrong config for Conical ESS turnpoint
allow Cone base altitude less than 0m
replace Radius by Slope for Conical ESS turnpoint in task Overview dialog
Merge branch 'ConicalESS' of https://github.com/brunotl/LK8000 into conical

Conflicts:
	Common/Header/Task.h