Use python 3.6 on Travis
Use python 3.6 on Travis

sorgerlab/belpy,johnbachman/belpy,sorgerlab/belpy,sorgerlab/indra,sorgerlab/indra,bgyori/indra,sorgerlab/belpy,johnbachman/indra,johnbachman/indra,johnbachman/belpy,johnbachman/belpy,johnbachman/indra,sorgerlab/indra,bgyori/indra,bgyori/indra