RF: named imports required in Python 3
RF: named imports required in Python 3

Cannot do ``from .module import *`` in Python 3.

FrancoisRheaultUS/dipy,JohnGriffiths/dipy,Messaoud-Boudjada/dipy,mdesco/dipy,samuelstjean/dipy,rfdougherty/dipy,nilgoyyou/dipy,jyeatman/dipy,samuelstjean/dipy,villalonreina/dipy,jyeatman/dipy,maurozucchelli/dipy,beni55/dipy,sinkpoint/dipy,StongeEtienne/dipy,oesteban/dipy,oesteban/dipy,samuelstjean/dipy,nilgoyyou/dipy,maurozucchelli/dipy,demianw/dipy,matthieudumont/dipy,FrancoisRheaultUS/dipy,demianw/dipy,matthieudumont/dipy,maurozucchelli/dipy,beni55/dipy,sinkpoint/dipy,JohnGriffiths/dipy,StongeEtienne/dipy,villalonreina/dipy,rfdougherty/dipy,mdesco/dipy,Messaoud-Boudjada/dipy