v0.5.1, add support for reading xlsx files…

[thammegowda]

v0.5.1: New datasets, formats, and bug fixes

New Features

• xlsx parser: Read Excel files via openpyxl (optional dependency). Handles Motorola's endangered language datasets which are distributed as .xlsx files
• csv parser: Proper CSV reader using Python's csv module for quoted fields with embedded commas. Fixes column misalignment in csvwithheader format
• --strict langpair ordering for mtdata list: mtdata list -l eng-deu --strict now only returns datasets stored in eng→deu order. Closes Allow strict langpair ordering #157
• HF data_files support: Load HuggingFace datasets by file path when config names aren't registered in the repo YAML (needed for SMOL smolsent/smoldoc)
• Generic SSL fallback: Retry downloads without SSL verification when certificate validation fails (e.g., hostnames with underscores violating RFC 952)
• Archive detection fix: entry.is_archive check before treating files as zip/tar, preventing .xlsx files (which are internally zip-based) from being misidentified

New Datasets

• Motorola Language Revitalization (8 datasets): eng-lld (Ladin), eng-chr (Cherokee), eng-xnr (Kangri), eng-mri (Maori), eng-yrl (Nheengatu), eng-kgp (Kaingang), por-yrl, por-kgp
• Google SMOL eng-lij: SmolSent (863 sentences), SmolDoc (825 sentences), GATITOS (4,332 lexicon entries)
• ZurichNLP wmt24pp-rm (6 Romansh varieties): Rumantsch Grischun, Sursilvan, Sutsilvan, Surmiran, Puter, Vallader (deu-roh test sets). Closes add wmt24pp-rm #178
• VistecAI scb-mt-en-th-2020 (12 CSV subsets): ~1M eng-tha sentence pairs. Closes Add Thai-English parallel corpus "scb-mt-en-th-2020" #151
• TALPCo (8 language pairs): jpn × {eng, kor, mya, zsm, ind, jav, tha, vie}. Closes Add TALPCo #152

Bug Fixes

• Strip \r from outputs: Fix carriage return leaking through in read_plain, read_tsv, and echo command. Closes Remove \r from outputs #173
• Fix TSV two-file pairing: Two separate TSV files now zip (pair) correctly instead of flattening
• Single-column TSV: cols=(1,) now yields scalar string instead of one-element list

Recipe Updates

• wmt26-eng-lld: Added Motorola eng-lld parallel data
• wmt26-eng-lij_Latn: Replaced NLLB (noisy) with SMOL smol_sent + smol_doc; added Tatoeba
• wmt26-eng-jpn: Added TALPCo jpn-eng

Closes

#157, #173, #178, #151, #152