Double decker cabin + Test improvements

[ngomezve]

• Added an optional input to make the cabin have two decks. In the future, the two decks could be sized independently but currently they are the same size.
• Removed equality requirement in some tests.
• Fixed IO test, wherein a csv file would be created and not removed. Also updated number of fields.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 58.33333% with 5 lines in your changes are missing coverage. Please review.

Project coverage is 73.95%. Comparing base (e70d62b) to head (07a1be3).

Files	Patch %	Lines
src/structures/update_fuse.jl	0.00%	4 Missing :warning:
src/sizing/wsize.jl	66.66%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #26 +/- ## ========================================== - Coverage 73.96% 73.95% -0.02% ========================================== Files 70 70 Lines 12978 12984 +6 ========================================== + Hits 9599 9602 +3 - Misses 3379 3382 +3 ```

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