TODO: faq, process a thing in each iteration
TODO: dbeugging tips, ev_verify, ev_init twice
+ - destroying a non-default loop would stop the global waitpid
+ watcher (Denis Bilenko).
- queueing pending watchers of higher priority from a watcher now invokes
them in a timely fashion (reported by Denis Bilenko).
- add throw() to all libev functions that cannot throw exceptions, for