made sure everything's thread safe

Pretty much everything already was, but I tweaked a few things to make
sure they stay that way and added various comments about that fact. Also
cleaned up a few things along the way and removed SafeMessageBuilder
because it wasn't.
27 files changed
tree: 07b86d777c70a74fcd48c25420052b627fefbbd7
  1. aos/
  2. bbb_cape/
  3. doc/
  4. frc971/
  5. output/
  6. vision/
  7. .gitignore
  8. README.txt