Pyyeti

- make compatible with scipy >= 1.8
- various updates to plotting in cla
- update logic and options for the "magpct" plots
- avoid using matplotlib.pyplot unless showing plots on screen
- add ytools.max_complex_vector_sum
- compute maximum complex vector from x and y components
- miscellaneous docstring updates & bug fixes

Minor update, primarily to add ytools.max_complex_vector_sum.

Added ytools.compmat - a matrix comparison tool
Moved read_text_file/write_text_file decorators from ytools to guitools

This is a relatively minor update:

- Updated some of the documentation examples to be compatible with Matplotlib 3.5.0.
- Updated how the `pre_eig` option is handled in SolveUnc to make it smarter
- Officially supports Python 3.9
- Fixed some bugs, mainly the bug in pyyeti.nastran.n2p.replace_basic_cs. It incorrectly used "0" for the rectangular type when it should use 1.

Fixed an issue with the output4 reader (pyyeti.nastran.op4) that caused it to fail on some reads. (pyYeti should be able to read all formats.) Thanks to Jeremy Priest for the bug report!

Also did some code cleaning & refactoring here and there.

Made the inner loop of the diagonal solver SolveUnc more efficient in terms of both speed and memory usage. Numba is used if available. Many thanks to Jeremy Priest for instigating this update! :) More updates like this are planned in the near future.

Documentation updates