Add cumulative simpson integration

[f0uriest]

Resolves #9

[codecov-commenter]

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Codecov Report

Attention: Patch coverage is 91.20879% with 8 lines in your changes missing coverage. Please review.

Project coverage is 93.83%. Comparing base (39eafa0) to head (d52a820).

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #12 +/- ## ========================================== - Coverage 94.33% 93.83% -0.51% ========================================== Files 7 7 Lines 530 616 +86 ========================================== + Hits 500 578 +78 - Misses 30 38 +8 ``` | [Files](https://app.codecov.io/gh/f0uriest/quadax/pull/12?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Rory+Conlin) | Coverage Δ | | |---|---|---| | [quadax/\_\_init\_\_.py](https://app.codecov.io/gh/f0uriest/quadax/pull/12?src=pr&el=tree&filepath=quadax%2F__init__.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Rory+Conlin#diff-cXVhZGF4L19faW5pdF9fLnB5) | `100.00% <100.00%> (ø)` | | | [quadax/sampled.py](https://app.codecov.io/gh/f0uriest/quadax/pull/12?src=pr&el=tree&filepath=quadax%2Fsampled.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Rory+Conlin#diff-cXVhZGF4L3NhbXBsZWQucHk=) | `88.11% <91.11%> (+1.91%)` | :arrow_up: |