v2.1.0

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: 2.0.9...2.1.0