Make streaming of files possible

[blancadesal]

See #5 for details

[blancadesal]

Copying from previous issue:

Streaming gzipped files using requests is indeed possible. 400kb seems to be enough to get all the metadata + at least the first INSERT INTO statement, even in the case of large files with many fields like enwiki page.

Example code:

URL = 'https://dumps.wikimedia.org/enwiki/latest/enwiki-latest-page.sql.gz'
r = requests.get(URL, stream=True)
with open("filename.sql.gz",'wb') as outfile:
    for chunk in r.iter_content(chunk_size=400000):
        if chunk: 
            outfile.write(chunk)
            break

This partial file can then be read as usual using gzip.open().