Move problem 1-2 (join) into project 2 as the "wait" system call.
[pintos-anon] / grading /
drwxr-xr-x   ..
-rw-r--r-- 249 Makefile
drwxr-xr-x - filesys
drwxr-xr-x - lib
drwxr-xr-x - threads
drwxr-xr-x - userprog
drwxr-xr-x - vm