Equality of ICoordinateSystem instances

[afroewis]

Hi,

I noticed an unexpected behavior when working with this library. I tried to check whether 2 coordinate systems are the same:

var crs1 = GeographicCoordinateSystem.WGS84;
var crs2 = GeographicCoordinateSystem.WGS84;

crs1 == crs2; // False
crs1.Equals(crs2) // False

Since coordinate systems are reference types, I think it makes sense that crs1 != crs2 if they don't refer to the same reference. However, since the contents of crs1 and crs2 are the same, I think it would make sense if crs1.Equals(crs2) is true.

Is this behavior desired? If not, I'd be happy to create a pull request (if that's possible for backwards compatibility reasons?).

Andreas