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.
diff --git a/aos/common/macros.h b/aos/common/macros.h
index 21482f6..e8558b2 100644
--- a/aos/common/macros.h
+++ b/aos/common/macros.h
@@ -8,6 +8,7 @@
#define DISALLOW_COPY_AND_ASSIGN(TypeName) \
TypeName(const TypeName&) = delete; \
void operator=(const TypeName&) = delete
+
// A macro to wrap arguments to macros that contain commas.
// Useful for DISALLOW_COPY_AND_ASSIGNing templated types with multiple template
// arguments.