Run tests with locally deployed NDT server

[bassosimone]

We were recently banned by AppVeyor because our tests were using too much outgoing bandwidth, I'd assume. Sadly, I did not know how I could throttle them as I did with Travis.

Now, this means that we need to make sure we can compile ndt-server on non-Linux systems, which should already be the case, and that it WAIs, which may or may not be the case.

However, this seems preferable to me to applying hacks to throttle tests.