feat(timeout): add timeout option for lazy estimators

[BenTenmann]

In some cases, some models will take much longer than others to fit. This can cause freezes, which is annoying. Here, I add an optional parameter for timeout, such that we can skip certain models if they run for too long.

[jlplenio]

Good idea, but will not work on Windows: https://stackoverflow.com/questions/52779920/why-is-signal-sigalrm-not-working-in-python-on-windows

[shankarpandala]

@BenTenmann Can you add documentation also for the same. Also, is this working on windows?