preserve original README and add a local branch README for clarity
remove packaging and printing support

This is really neat but is not going to get along well with the code
shuffling I'm doing, so just removing it for now.
move rest of source code to subdirs, tidy the build a bit

kernel source lives in kernel/...
user library source lives in ulib/...
tools live in tools/...
kernel and userspace objects are generated in kobj/... and uobj/...
intermediates are generated in out/...
contents of the filesystem are generated in fs/...

kernel/main.c and kernel/proc.c had to be adjusted due to the out/...
path affecting the symbol names for the initcode and entryother blobs

tools/mkfs.c is adjusted to allow fs/... prefixes
update readme
a bit more cleanup
x86: add hlt() wrapper
scheduler: halt and wait for irq if nothing was scheduleable

h/t tankenmate@hackernews who did this a bit more verbosely
https://news.ycombinator.com/item?id=6974384