os: implement ReadWriteLock

ams: finish stdio -> fs bindings for stratosphere

stratosphere-except-ldr: use fs bindings (this temporarily breaks loader)

util: add uuid

ams: revamp assertion system

kern: use TinyMT instead of mt19937_t

find -exec sed -i'' -e 's/2018-2019 Atmo/2018-2020 Atmo/g' {} +

Fix another off-by-one in TinyMT init calcs

tinymt: correct init iter count

random: use TinyMT instead of XorShift

git subrepo clone https://github.com/Atmosphere-NX/Atmosphere-libs libraries ...

subrepo:
  subdir:   "libraries"
  merged:   "07af583b"
upstream:
  origin:   "https://github.com/Atmosphere-NX/Atmosphere-libs"
  branch:   "master"
  commit:   "07af583b"
git-subrepo:
  version:  "0.4.0"
  origin:   "https://github.com/ingydotnet/git-subrepo"
  commit:   "5d6aba9"