grid convergence should be computed for all georeferenced data

[Eric C. Landgraf]

Currently, grid convergence is calculated only when *declination auto is set (with a representative coordinate). For normal people dealing with normal data, this is fine.

However, if any survey has *declination set to a fixed value, this is treated as the difference between Magnetic north and North in the output coordinate system (i.e. grid north).

IF input and output coordinates systems are set, we should *always* compute grid convergence, as that is an expected (and potentially impactful) difference.