Implement Path-like division operators.

[amcgregor]

Examples:

from uri import URI

base = URI("http://example.com/foo/bar.html")

base / "baz.html"  # http://example.com/foo/baz.html
base // "cdn.example.com" / "baz.html"  # http://cdn.example.com/baz.html
base / "/diz"  # http://example.com/diz
base / "#diz"  # http://example.com/foo/bar.html#diz
base / "https://example.com"  # https://example.com

A concrete example:

base = URI("http://ats.example.com/job/listing")

# scrape the listing, identify a job URL from that listing
target = URI("detail/sample-job")  # oh no, it's relative!

job = base / target  # And it's resolved.