Add a queue_peek function to look at the next byte without popping.
Add a queue_peek function to look at the next byte without popping.

openxc/vi-firmware,ene-ilies/vi-firmware,openxc/vi-firmware,ene-ilies/vi-firmware,mgiannikouris/vi-firmware,ene-ilies/vi-firmware,ene-ilies/vi-firmware,mgiannikouris/vi-firmware,mgiannikouris/vi-firmware,mgiannikouris/vi-firmware,openxc/vi-firmware,openxc/vi-firmware