Fix warning in mclearn.viz.plot_hex_map. Solves #149.
Fix warning in mclearn.viz.plot_hex_map. Solves #149.

chengsoonong/mclass-sky,chengsoonong/mclass-sky,alasdairtran/mclearn,chengsoonong/mclass-sky,alasdairtran/mclearn,alasdairtran/mclearn,chengsoonong/mclass-sky,alasdairtran/mclearn