Fixed an issue in phenotypic_phase_plane not resetting to the original model objective
Install zmq with apt-get and install bokeh, pandas, and pyzmq from wheelhouse
Merge branch 'devel' of github.com:biosustain/cameo into devel

Conflicts:
	.travis.yml
Skipping tests that stall on travis
Skipping tests that stall on travis
Merge branch 'devel' into heuristic_methods

Conflicts:
	tests/test_strain_design_heuristics.py