stub: use arbitrary field for feature ID
stub: use arbitrary field for feature ID

Forget Z/M logic, didn't work and is not what I want anyway! Abstract to
using any field for individual feature ID (Name, Label).

Also use arcpy.Describe because apparently bug in gp.describe() has
never been fixed arcgisscripting (v9.x).  c.f. Esri CQ00247755,
http://forums.esri.com/Thread.asp?c=93&f=1729&t=132176&g=1

maphew/arcplus,DougFirErickson/arcplus,maphew/arcplus