a whole lot of warnings when unit tests are run

[lspitler]

We've added:
-p no:warnings
to setup.cfg.

These are nearly all depreciation warnings, so this implies we need to fix just a few instances of outdated usage of e.g.:

gunagala/tests/test_optical_filter.py::test_aoi /Users/lspitler/miniconda3/envs/huntsman/lib/python3.7/site-packages/astropy/units/quantity.py:1060: AstropyDeprecationWarning: The truth value of a Quantity is ambiguous. In the future this will raise a ValueError. AstropyDeprecationWarning)

unagala/tests/test_camera.py::test_camera /Users/lspitler/miniconda3/envs/huntsman/lib/python3.7/site-packages/asdf/reference.py:11: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated, and in 3.8 it will stop working from collections import Sequence

/Users/lspitler/miniconda3/envs/huntsman/lib/python3.7/site-packages/matplotlib/backend_bases.py:57: DeprecationWarning: PILLOW_VERSION is deprecated and will be removed in a future release. Use __version__ instead. from PIL import PILLOW_VERSION

gunagala/tests/test_imager.py::test_create_imagers /Users/lspitler/prog/gunagala/gunagala/config.py:138: YAMLLoadWarning: calling yaml.load() without Loader=... is deprecated, as the default Loader is unsafe. Please read https://msg.pyyaml.org/load for full details. c = yaml.load(f.read())

gunagala/tests/test_imager.py::test_snr_vs_mag[r-SSO] /Users/lspitler/miniconda3/envs/huntsman/lib/python3.7/site-packages/astropy/units/quantity.py:477: RuntimeWarning: invalid value encountered in true_divide result = super().__array_ufunc__(function, method, *arrays, **kwargs)