[WIP] Add capability to perform socket based tests

[sivel]

This PR aims to add the ability to perform socket based tests in addition to the current HTTP based tests.

python speedtest.py --socket

[dlenski]

Any plans to merge this, or help needed to get there?

I know that it's a non-goal to exactly match the results of the speedtest.net web interface, but it's notable to me that the results are much more closely matched to the web interface when using socket-based tests, particularly in the upload direction.