Add unwrap option to http.unshortenUrl

Delete debug print

Implement knu.utils.execute as a drop-in replacement for hs.execute

Document knu.utils.string

Add some well-known link tracking domains to http.shortenerHosts

Reduce logging in unshortenUrl

http.unshortenUrl recognizes subdomains of http.shortenerHosts

Adjust require() calls so they work in a Spoon