array2hist: return the hist to allow chaining and list comprehensions
array2hist: return the hist to allow chaining and list comprehensions

ibab/root_numpy,ndawe/root_numpy,scikit-hep/root_numpy,rootpy/root_numpy,ndawe/root_numpy,ibab/root_numpy,rootpy/root_numpy,scikit-hep/root_numpy,ndawe/root_numpy,rootpy/root_numpy,scikit-hep/root_numpy,rootpy/root_numpy,ndawe/root_numpy,ibab/root_numpy,scikit-hep/root_numpy,ibab/root_numpy