Rayoptics

=============
Get dependencies correct for Python 3.8 on conda-forge and ReadTheDocs. Last release for Python 3.8

=============
Implement a :class:`~.oprops.doe.DiffractionGrating` with ray trace and opd calculations. Add ability to draw single rays and control their color. Fix issues 102 (defocus application), 107 (Zemax import), 110 (defocus and image shift), 114 (Zemax import), 115 (ray aiming), 124 (immersed image), 125 (Zemax constant index), 127 (model modifications), 138 (local loggers).
There were a variety of small fixes and improvements, e.g. to :func:`~listobj`.
Thanks to mpetroff and dominikonysz for their contributions to **ray-optics**.

=============
Fix crashing issue 101. Adjustments to the :mod:`~.medium` package. Remove many work files that weren't in the repo.

=============
Improve :meth:`~.seq.sequential.SequentialModel.add_surface` handling of materials and semi-diameter.
Maintenance work on ray trace related issues, esp. aperture handling for list and grid traces.
Move functionality in :mod:`~.seq.medium` into the :mod:`opticalglass` package and update code.
Remove jupyterlab and ipympl from the installation. These should be installed as desired by the user.
Fix a ray trace bug in XToroid profile; other miscellaneous bug fixes.
Revise doc to use RTD yaml file; other doc updates.

=============
Add :func:`~.gui.appcmds.set_pupil` function to set the pupil specification based on the aperture stop size. Add a hole feature to :class:`~.elem.elements.Element` and :class:`~.elem.elements.Mirror`. InteractiveLayout will draw holes but they haven't yet been included in the sequential model or the ray trace. The :meth:`~.seq.sequential.SequentialModel.add_surface` method was fixed and enhanced to take additional inputs for materials and allow use of a `sd` keyword argument to specify the semi-diameter of the surface. A variety of bug fixes were made to import and saving of models as well as other fixes; see the update log for specifics. All of the .roa files on the distro were restored and saved with the current version. At the same time, the long deprecated Pupil and Field enums were removed from the code. Finally, the build and packaging of **ray-optics** was updated to use current python technologies.

=============
Fixes to drawing cemented element flats when the inner surfaces intersect the outer flats. Accept URLs from the OpticalBench database as arguments to :func:`~.gui.appcmds.open_model`. Enhance :func:`~listobj` output for :class:`~.seq.sequential.SequentialModel` and :class:`~.seq.gap.Gap`. Bump pyqt5 compatibility to v5.15.