Added back in swap_is_on_disk
placed swap is on disk in frame call, moved frees to end of process exit
Added pinning
Added pinning calls to syscall
Merge branch 'reverted' into mmap-merged

Conflicts:
	src/threads/thread.c
	src/threads/thread.h
	src/vm/frame.h
	src/vm/swap.h
removed panicking on check
Merge branch 'reverted' of github.com:odiab/cs140 into HEAD
Fixed misc bugs, cleaned up codebase
Merge branch 'mmap-merged' into matt-code

Conflicts:
	src/threads/thread.c
	src/vm/frame.c
	src/vm/swap.h
removed pinning, made frames carry threads, fixed swap freeing
cleaned up swap code a little
Moved around methods into sections
fixed race condition with syscall exit
Merged in stash
removed printfs
refactored frame assign methods, mmap write prototype
implemented mmap read and write, not tested
refactored frame_retrieve_evicted_vaddr, added mmap version