update arcpy.CreateGPSDDraft documentation

CharlesArnold

Add a note in the documentation for the arcpy.CreateGPSDDraft function (http://resources.arcgis.com/en/help/...0000008z000000) that it only works with .tbx toolboxes, and there's no way to get it to work with python toolboxes.  Would have saved me some time digging thru documentation to find what I was missing, only to end up empty.

Better yet, make the descriptions can just be made optional.

http://forums.arcgis.com/threads/103083-ERROR-001242-when-calling-arcpy.CreateGPSDDraft-with-result-from-.pyt-toolbox