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.