I broke poll with commit 8deb0ebd041ab6d4761f86a7a906dd850111bae7

The result is just fine for calling poll() only once, but breaks for
subsequent calls to poll() when passing the same table. In this case,
the events are not cleared from the revents table, causing false
positives.
Merge pull request #95 from zevv/fix-poll

I broke poll with commit 8deb0ebd041ab6d4761f86a7a906dd850111bae7