Archive all email text that came in, instead of just restricting to
comments

There's relevant information here anyway

But also get rid of the email footer ;) It always just repeats itself.
We don't need it!
Use a hash of the comment body to determine uniqueness

This is so that all items without a comment number don't overwrite one
another (as comment 0), leaving us with only one of them recorded.

Deliberately not checking the date, because that might differ between
data sources depending on timezone