Cherrypick v0.12 doc updates
Cherrypicked commits from https://github.com/joyent/node/pull/25635
These include a handful of doc and comment fixes that landed in v0.12. Some of the commits had to be updated slightly to land.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Cherrypicked commits from https://github.com/joyent/node/pull/25635
These include a handful of doc and comment fixes that landed in v0.12. Some of the commits had to be updated slightly to land.