Let moderators select multiple messages in the mod queue in order to mass accept/reject

[amyxzhang]

make sure we have enough warnings/signals in case there's harassing stuff later on, like the perspective API stuff, presence of certain words, etc.

[kmahar]

Yes, this was a highly requested feature by mods in the user study. I think they were most frequently annoyed when they were approving large numbers of automated marketing, etc. emails.