DOC, BW: Minor changes on dipy.sims.voxels.py: 1) Insert new example of the use of function multi_tensor_dki (DOC); 2) insure that dt and kt are arrays in function single_diffkurt_tensors (BW)
DOC, BW: Minor changes on dipy.sims.voxels.py: 1) Insert new example of the use of function multi_tensor_dki (DOC); 2) insure that dt and kt are arrays in function single_diffkurt_tensors (BW)

matthieudumont/dipy,demianw/dipy,sinkpoint/dipy,matthieudumont/dipy,oesteban/dipy,demianw/dipy,sinkpoint/dipy,StongeEtienne/dipy,nilgoyyou/dipy,JohnGriffiths/dipy,FrancoisRheaultUS/dipy,villalonreina/dipy,jyeatman/dipy,nilgoyyou/dipy,StongeEtienne/dipy,villalonreina/dipy,rfdougherty/dipy,JohnGriffiths/dipy,oesteban/dipy,jyeatman/dipy,FrancoisRheaultUS/dipy,rfdougherty/dipy