|index||The index of the existing path to duplicate.|
This function takes a path and copies it into a new path. The
new path is created in the process, and the index is returned to be
used in all further calls to use this new path.
mypath = path_duplicate(choose(path_1, path_2, path_3, path_4));
The above code chooses one of four path resources and duplicates it, storing the index of the new path in the variable "mypath".