add support for a fixed number of proxies that are *always* used

[rofl0r]

e.g. for having tor fixed as first proxy, then using the rest for
random selection.

[twine-mark]

This is amazing. Any reason that it is still not merged for two years?

[rofl0r]

insufficient testing. you could be the one

[bitsydarel]

This is perfect for my current use case, how can i help with the testing ?

[rofl0r]

@bitsydarel just build the code from the branch and use it for a couple days in everyday scenarios. then report your findings and describe roughly what you were doing.