Major revisions to documentation and assignments.
Implement good solutions to all assignments.
Rewrite pintos script, fsutils, and Pintos command line parsing to
support put, get of multiple files.
New pintos-mkdisk script for what pintos doesn't do anymore.
Make backtrace more friendly.
Major revisions to base file system.
Get rid of names passed to synch primitives.
Break intr_register() into intr_register_ext() and intr_register_int().
Revise bitmap code.
Add console_locked_by_current_thread() and use it.
munmap() has void return value (in lib/user/syscall.c).
Update expected tools versions.
Document use of qemu.
Add realloc() function to malloc implementation.
Add is_user_vaddr() and is_kernel_vaddr(), use in mmu.h.
Add sema_try_down(), lock_try_acquire().
Add memory barrier.
Extend default time slice to 4 ticks and calculate time slices
properly (don't just switch whenever timer_ticks() % 4 == 0).
Fix writing to palloc'd memory without checking against null
in pagedir_create().
Invalidate TLB when we mark pages not accessed or not dirty.
Revise other pagedir code.
Make load() less nasty-looking.