Update more tolerance usages, add a few docstring and unit test

[jcao-bdai]

• another pass by searching and checking all _eps usages (previously missed when searching with tol keyword);
• fix a few docstring issues;
• fix a minor bug in angle_wrap;
• improve test coverage for math methods (passing up visualization methods for now).

[codecov[bot]]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (fd9e6a0) 75.62% compared to head (6939ed8) 76.49%.

:exclamation: Current head 6939ed8 differs from pull request most recent head a81c21c. Consider uploading reports for the commit a81c21c to get more accurate results

Files	Patch %	Lines
spatialmath/quaternion.py	50.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #106 +/- ## ========================================== + Coverage 75.62% 76.49% +0.86% ========================================== Files 24 24 Lines 5132 5134 +2 ========================================== + Hits 3881 3927 +46 + Misses 1251 1207 -44 ```

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