updated step docstring, removed qtgui import in step.py
Merge branch 'master' of ssh://bitbucket.org/jangle/pointwiserigidregistrationstep
Merge branch 'master' of ssh://bitbucket.org/jangle/pointwiserigidregistrationstep
Merge branch 'master' of bitbucket.org:jangle/pointwiserigidregistrationstep