DOC: Update minimum dependency for numpy, mailing list.
DOC: Update minimum dependency for numpy, mailing list.

matthieudumont/dipy,StongeEtienne/dipy,FrancoisRheaultUS/dipy,villalonreina/dipy,FrancoisRheaultUS/dipy,nilgoyyou/dipy,matthieudumont/dipy,nilgoyyou/dipy,villalonreina/dipy,StongeEtienne/dipy