Timeout parameter for autotuner

[fftobiwan]

Thanks for your great library. I just started to play around with TC.

I experience that some of the initial jobs created by the autotuner in generation 0 run for a very, very long time (3-4 orders of magnitude slower than the fastest of the initial jobs). It would be nice to pass a timeout parameter after which jobs are automatically aborted.

[ftynse]

potential duplicate of #381

[concretevitamin]

+1. This will be tremendously more user-friendly. When a single job becomes the straggler orders-of-magnitude slower (than any of best, median, or worst), it does not make sense to continue running it. Also ctrl-c only seems to work 50% of the time :)