Poll events in new thread, don't rely on kqueue's backend fd anymore.
Poll events in new thread, don't rely on kqueue's backend fd anymore.

Part of fixes for rogerwang/node-webkit#82.

patrickm/chromium.src,patrickm/chromium.src,ondra-novak/chromium.src,littlstar/chromium.src,patrickm/chromium.src,patrickm/chromium.src,littlstar/chromium.src,patrickm/chromium.src,littlstar/chromium.src,patrickm/chromium.src,patrickm/chromium.src,littlstar/chromium.src,ondra-novak/chromium.src,littlstar/chromium.src,ondra-novak/chromium.src,littlstar/chromium.src,ondra-novak/chromium.src,ondra-novak/chromium.src,ondra-novak/chromium.src,ondra-novak/chromium.src,ondra-novak/chromium.src,ondra-novak/chromium.src,littlstar/chromium.src,patrickm/chromium.src,patrickm/chromium.src,littlstar/chromium.src