Automate checking binary/continous data

[cthoyt]

As a follow-up to #193, this PR extends the default conditional independency test from just being the Cressie-Read test to dynamically checking if the data is binary or not. If it's binary, it stays with cressie read but if it's continuous, it sets it to the Pearson test.

This implementation doesn't yet consider discrete data with more than 2 values. The idea Pruthvi had in eliater was to manually specify a threshold. I don't like this since it's parametric, and if you already know what's going on in your data, you might as well set the test correctly. An idea for an automated test is in here for future reference: https://stats.stackexchange.com/questions/12273/how-to-test-if-my-data-is-discrete-or-continuous

[codecov[bot]]

Codecov Report

Attention: 7 lines in your changes are missing coverage. Please review.

Comparison is base (bc2317c) 77.26% compared to head (5561b1a) 77.74%. Report is 1 commits behind head on main.

Files	Patch %	Lines
src/y0/struct.py	80.95%	2 Missing and 2 partials :warning:
src/y0/algorithm/falsification.py	66.66%	2 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #194 +/- ## ========================================== + Coverage 77.26% 77.74% +0.47% ========================================== Files 45 45 Lines 3040 3065 +25 Branches 676 684 +8 ========================================== + Hits 2349 2383 +34 + Misses 599 583 -16 - Partials 92 99 +7 ```

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