v0.1.1: first archived release

Identical in content to v0.1.0 (see its notes for the full description and the closed-form validation list); this release exists so the package's Zenodo archive begins with its first preserved version, now that the repository is connected to Zenodo. Also the first version whose PyPI upload runs through the configured trusted publisher.

One tight-binding Hamiltonian, every observable: bands, DOS, Kubo-Greenwood optical conductivity and Landauer (NEGF) transmission from the same real-space blocks, nonorthogonal bases included. Validated against closed forms (23 tests). Dependencies: NumPy and SciPy.