Michael Gratton authored Mar 09, 2019 and Michael Gratton committed Mar 09, 2019

Some software like the above will mangle From mailbox names by appending
"via Some Service" to the From mailbox name. This messes up generating
default avatars for the actual people sending these messages, so
attempt to de-mangle the names.

This involves moving primary originator determination from the engine
to the client, since it's now a policy thing. Add unit tests.