added routine to compute Kleinjung's L2 norm

git-svn-id: 189946a10c5fc96e9dd03ba7cba917cd4c3d09f4@1300 de4796e2-0b1e-0410-91b4-86bc23549317

remote: Support for password authentication was removed on August 13, 2021.
remote: Please see https://docs.github.com/en/get-started/getting-started-with-git/about-remote-repositories#cloning-with-https-urls for information on currently recommended modes of authentication.
fatal: Authentication failed for 'https://github.com/mancoast/cado-nfs.git/'