drawGD: Generic called on each gdObject to do the plotting.
Description
This generic gets called on each of the gdObjects (obviously the
generic is implemented by a method for each object) and thus if a user
wishes to implement new gdObjects they need to have access to this
generic.
Usage
drawGD(gdObject, minBase, maxBase, vpPosition, ...)
Arguments
gdObject
gdObject list to plot
minBase
Minimum base position to plot
maxBase
Maximum base position to plot