qemu-tap added, based on:

 * https://superuser.com/questions/596095/how-do-i-bridge-a-connection-from-wi-fi-to-tap-on-mac-os-x-for-the-emulator-qe
 * http://en.blog.guylhem.net/post/88201449689/running-qemu-with-tap0-and-nat-under-osx-10-9-maverick

Signed-off-by: Christian Kujau <github@nerdbynature.de>