Changing the registration.confidence function to be consistent with chen 2012, eqn 14 - this prob needs checking. Also, actually including the confidence paramter that was omitted from qtildematrices.
The previous commit did not add the confidence parameter in correctly. Updated to do it properly.
Gah! correcting the stupid error from the last commit.
Merge pull request #103 from hgomersall/master

Make use of confidence parameter in registration.

Closes #102.