Implement syscall framework
Merge branch 'cp3-pcb' into cp3-syscalls
Add command to fetch PCB of current process
Fix proc.h misc issues
Add typedefs for function pointers
Implement read,write, open Sys_calls
Do work on exec syscall
Merge remote-tracking branch 'origin/cp3-syscalls' into cp3-syscalls
Merge branch 'cp3' into cp3-syscalls
Uncomment critical code
Work more on halt
Do more work on syscalls
Fix issues brought up by last commit
Final push before turnin
Add work on exec syscall
Finish first implementation of exec system call finally. The OS can now run one program at a time.