Needs remove function

[GoogleCodeExporter]

What steps will reproduce the problem?
1. There isn't a .remove(prefix) function as there is in the Perl equivalent.

What is the expected output? What do you see instead?
The tree will no longer hold the IPv4/6 prefix in its tree

What version of the product are you using? On what operating system?
version 5 on Ubuntu 12.10

Please provide any additional information below.

Original issue reported on code.google.com by Lawrenc...@gmail.com on 26 Mar 2013 at 5:07