New function to return cg of an object

[Mike Bartholomew]

It is becoming clearer that when locating objects that are offset from the primary Alignment, and/or are unsymmetrical, they get moved vertically based on where the object's center of gravity is and its transverse offset. I think we need a function to determine the center of gravity from the the zero reference point of the object, so that we can apply the alignT function to adjust its position vertically. Although this is described as an enhancement, it really will help correct graphic inconsistencies and could be looked at like a bug.

[Ali Koc]

Do we still need this functionality, now that we have alignT(), alignV() and alignH() functions?

[Ali Koc]

We can open this again if we come across a case where we need object cog function.