Additional testing for tracker and tx modules - mostly around serialization/deserialization

[derekpierre]

Based over #27

Fixes #29 Fixes #15

• Tested serialization/deserialization of tracker information
• Fixes issues arising with serialization of tx objects
• Considerations made for eq has hash comparisons - pay special attention there when reviewing

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 99.35424% with 7 lines in your changes are missing coverage. Please review.

:exclamation: No coverage uploaded for pull request base (main@6248d7d). Click here to learn what that means.

Files	Patch %	Lines
atxm/machine.py	96.10%	3 Missing :warning:
atxm/tx.py	92.59%	2 Missing :warning:
tests/test_machine.py	99.41%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #30 +/- ## ======================================= Coverage ? 97.92% ======================================= Files ? 15 Lines ? 2022 Branches ? 0 ======================================= Hits ? 1980 Misses ? 42 Partials ? 0 ```

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[derekpierre]

Coverage as of https://github.com/nucypher/ATxM/pull/30/commits/3245c0fff0813e1070e9eef572c170650e43e444: