[MlMt] Automatic set from email depending on "to email"

[Michael Nietzold]

summary:

i have a seperate email adress set for the freron email ist. but because 
the mails from this list don't are something special (they not not have 
my email in the `TO:` header). but if i hit reply i always need to 
remember to set this special email as `from` for this email.

when:

- i get mailmate list
- i hit reply


what i see:

- it uses my default email

what i expect:

- it should remember that i used a different eMail
- or a setting (dict) like the `MmDefaultBccHeader`, where i can set 
some adress for some `to`


Example:

`defaults write com.freron.MailMate MmDefaultFromHeader -dict 
"mailmate at lists.freron.com" "myspecialemail at example.com"`
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freron.com/pipermail/mailmate/attachments/20190401/d27140a7/attachment.html>