fix: no timeout for urlopen issue #526

[grzracz]

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[CLAassistant]

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[jannotti]

urlopen docs say: The optional timeout parameter specifies a timeout in seconds for blocking operations like the connection attempt (if not specified, the global default timeout setting will be used). Any idea what that global is?

Regardless, it seems right to me to let the caller have access to the setting. I'd like @jasonpaulos to weigh in.

Another possible is to allow arbitrary **kwargs, and pass them through, if there are other useful features of urlopen that it would give access to. It doesn't seem like it though, the rest appears to about SSL details.

[grzracz]

Seems like the default timeout is implementation-dependent and in Python it just never times out:
https://stackoverflow.com/questions/29649173/what-is-the-global-default-timeout

[jasonpaulos]

This looks like a good improvement. Thanks for the contribution