Make bodyparsing hashing work for more mail clients

[Divide-By-0]

Thanks to MV for the bug report.

Apparently apple mail automatically splits strings with the soft returns, and uses = for them, while also replacing the = in base64 padding with =3D

you can sidestep it by enforcing line lengths

Skiff and some other clients don't introduce any breaks, gmail web client introduces hard returns every 75 chars, apple mail introduces these weird soft returns every 75 chars.

Seems like it would be really hard to account for all of these things in one circuit

Apple mail is specifically annoying because the simplest version of this email is just a base64 string of the encoded tx, and introducing random = padding chars really messes stuff up