Ensure that "caught" errors are not emitted as "uncaughtException".

Fixes #13.

It looks like that the issue was exactly https://github.com/joyent/node/issues/4375 fixed with https://github.com/joyent/node/commit/4401bb47bfa4fe72c2755c428577903ece5cfaa0.

This fix adds a workaround to tests, since it's not something that should be fixed in asap.