Add a shell prog
Fix bug when reading partial line from stdin
Fix some term memory issues
Fix an init error in process
Remove some unused defs from asm
Another x86 structure alignment fix

header words need to be mod 8 + 2, not mod 4 + 2
Fix another bug with page init
CLI at software interrupt

Software interrupts do not automatically clear I flag in rflags, was
causing disasters
Fix clobber list for syscalls
Sleep does not need to call schedule anymore
Remove kmode check on yield syscall

doesn't really matter
Inbuf should clear buffer on init
Move userspace mem defs to one place
Move user stack to actual top of memory

in canonical addressing, end addresses are at actual end of 64-bit space