Neural-admixture

- Added direct binary PLink file format (BED) compatibility.
- Added an early stopping criterion (stops when difference between subsequent objective function value is less than `tol`, which defaults to 1e-6).
- Added TSVD-KMeans initialization method, which should be faster (default is still PC-KMeans).
- Dimension of principal component space where K-Means is computed during the initialization step can now be passed as an argument.

- Refactor into PyPI package.
- UX updates.
- Documentation update.

- Semi-stable version.
- Added inference script.

- Software is now compatible with VCF files.
- Same output format as ADMIXTURE.
- Software now expects ground-truth population file format used in ADMIXTURE (plain txt) for the supervised mode.