defaultList: Add Default Elements to Incomplete list
Description
Given two lists elemets (by name) missing from the first are copied from the
second list (if present). Is used to create default lists, ensuring that all
elements expected in the list are present with reasonable values (if not
user specified).
Usage
defaultList(x, prototype = list())
Arguments
x
A list
prototype
A list with named elements, any elements missing from
x are replaced with corresponding elements from prototype.