[BUG] Missing dependencies on pypi install

[lucpeterson]

Describe the bug
pip install from pypi doesn't grab all the necessary dependencies

To reproduce

1. python3 -m virtualenv "testy"
2. source testy/bin/activate
3. pip install merlinwf
4. merlin
   -> breaks
   "ModuleNotFoundError: No module named 'tabulate'"
5. pip install tabulate
6. merlin
   -> breaks
   ModuleNotFoundError: No module named 'maestrowf'
7. pip install -e git+https://github.com/LLNL/maestrowf.git#egg=maestrowf
8. merlin
   -> success

Expected behavior
pip install merlinwf should grab all dependencies

[lucpeterson]

#31

[ben-bay]

tabulate has been added to release.txt on develop, and will be fixed in the next upload to PyPI. maestrowf, however, remains a problem.

[koning]

maestrowf fixed with #42

[ben-bay]

maestrowf fixed with #42

...or so we thought. PyPI isn't allowing URL installs, so for now we wait until Maestro on PyPI gets load_specification_from_stream in v1.1.5, which Frank says whould come later today.