greeners 1.4.0

High-performance econometrics with R/Python formulas. Two-Way Clustering, Marginal Effects (AME/MEM), HC1-4, IV Predictions, Categorical C(var), Polynomial I(x^2), Interactions, Diagnostics. OLS, IV/2SLS, DiD, Logit/Probit, Panel (FE/RE), Time Series (VAR/VECM), Quantile!
Documentation
# Contributing to Greeners

First off, thank you for considering contributing to Greeners! We are an open-source project and we love to receive contributions from our community.

## Contribution Process

1.  **Fork** the repository.
2.  Create a **branch** for your feature or fix (`git checkout -b feature/amazing-feature`).
3.  **Commit** your changes.
4.  **Push** to the branch.
5.  Open a **Pull Request**.

## ⚖️ Legal Terms and Licensing (Important)

By submitting a Pull Request (PR) to this repository, you agree to the following terms:

1.  **Authorship:** You declare that the submitted code is your own work or that you have the necessary rights to submit it.
2.  **Rights Grant:** You grant the project maintainer (**[Flávio de Vasconcellos Corrêa (sheep-farm)]**) a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable license to use, modify, distribute, and sublicense your contribution.
3.  **Dual Licensing Consent:** You explicitly understand and accept that the project maintainer may distribute your contribution under the current license (GPLv3) **and/or under future proprietary commercial licenses** (Dual Licensing), without the need for further notification or compensation.

**TL;DR:** The code remains free and open for the community (GPLv3), but the maintainer retains the right to offer alternative commercial licenses to companies to ensure the project's sustainability.

---
If you have any questions, please open an issue before submitting your code!