ENH: Update CleaverExtension extension

This updates the CleaverExtension extension to
25385dc1f20745898a3e6546d1df41db07817adf.
Merge pull request #742 from pnlbwh/update-FinslerTractography

Update FinslerTractography
Merge pull request #743 from pnlbwh/update-UKFTractography

Update ukf tractography
Merge pull request #741 from brigb123/update-CleaverExtension-master

ENH: Update CleaverExtension extension
Updating description in the extension file of UKFTractogrpahy