TEST: added test that shows how the boundary is preserved by the use of nlmeans
TEST: added test that shows how the boundary is preserved by the use of nlmeans

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