Fix bug where pyproj transformations returned by `generate_map_coordinates` could have an inconsistent positive longitude direction with other parts of PlanetMapper

[ortk95]

All transformation objects used to default to +E longitudes, which could cause issues for +W bodies. This update now explicitly defines the coordinate axes for all transformations so that +E bodies have the +axis=enu convention and +W bodies have +axis=wnu convention. This ensures that the transformation objects should now always work as expected, having the same positive longitude direction as the rest of PlanetMapper.

Closes #289

Pull request checklist

• [ ] Add a clear description of the change
• [ ] Add any new tests needed
• [ ] Run spell check on new text visible to user (documentation, GUI etc.)
• [ ] Check any changes to requirements.txt are reflected in setup.py
• [ ] Check code passes CI checks (run run_ci.sh or check GitHub Actions)

See CONTRIBUTING.md for more details.

[coveralls]

Pull Request Test Coverage Report for Build 6459319024

• 14 of 14 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.002%) to 99.5%

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Totals
Change from base Build 6419867482:	0.002%
Covered Lines:	2759
Relevant Lines:	2773

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💛 - Coveralls