Fix biggraphite install
Fix biggraphite install

IPython6 need python>3.3, so we force ipython<5

iksaif/biggraphite,criteo/biggraphite,Thib17/biggraphite,iksaif/biggraphite,Thib17/biggraphite,dpanth3r/biggraphite,Thib17/biggraphite,criteo/biggraphite,iksaif/biggraphite,iksaif/biggraphite,Thib17/biggraphite,criteo/biggraphite,criteo/biggraphite