Summary: Fixes an issue with calculating currents with TPXO9-atlas models in netCDF4 format (thanks @mirkorupani!). Changes how nodal arguments for constituents are calculated. Program now uses linear algebra with a table of Doodson coefficients (Cartwright numbers), which should hopefully be more transparent and extendable. This also allows the easy calculation of Doodson or Cartwright numbers for constituents (thanks @q1165600785!). Itemized Changes: fix: revert TPXO9-atlas currents changes to separate dicts for #258 (#259) test: fix u and v for TPXO9-atlas netCDF (#259) fix: escape sequences in docstrings to raw (#259) fix: updated ssl context to fix deprecation error (#259) docs: update docstrings for ssl context (#259) refactor: use doodson arguments tables to calculate values (#270) refactor: rename phase_angles to doodson_arguments (#270) refactor: coordinate reference system class crs.py (#270) refactor: pass through VBox and HBox in tools.py (#270) docs: add link to TMD3 in Resources.rst (#270) feat: made keyword argument for selecting M1 coefficients (#270) feat: add initial solver for harmonic constants (#270) chore: include whitespace after commas (#270) feat: add function to create arguments coefficients table (#270) test: add check that arguments match prior version (#270) docs: started creating a glossary (#270) docs: add citation to Simon et al. (1994) (#270) feat: create arguments coefficients table for minor constituents (#270) feat: add function to calculate Doodson numbers for #263 (#270) refactor: use mean lunar time as independent variable (#270) refactor: moved minor arguments calculation into new function (#270) refactor: implicit import of arguments (#270) test: add check for constants solve (#270) feat: add functions to convert to and from Doodson numbers (#270) feat: add option to output Cartwright numbers (#270) feat: add properties for Doodson and Cartwright numbers to constituents class (#270) feat: try to get the constituents of FES files (#270) Full Changelog: https://github.com/tsutterley/pyTMD/compare/2.0.9...2.1.0