Update lab04.md
Update lab04.md
UCSB-CS56-F17/ucsb-cs56-f17.github.io,ucsb-cs8-m17/ucsb-cs8-m17.github.io,UCSB-CS56-F17/ucsb-cs56-f17.github.io,UCSB-CS56-F17/ucsb-cs56-f17.github.io,ucsb-cs8-m17/ucsb-cs8-m17.github.io,UCSB-CS56-F17/ucsb-cs56-f17.github.io,ucsb-cs8-m17/ucsb-cs8-m17.github.io,UCSB-CS56-F17/ucsb-cs56-f17.github.io,ucsb-cs8-m17/ucsb-cs8-m17.github.io,ucsb-cs8-m17/ucsb-cs8-m17.github.io