s/TMail/Mail ; fix history function

[nerdyness]

Hi @auxesis

This will take care of both issues I've raised :)

• it gets rid of TMail
• the history function works for @TimCorcoran's ticket (RT1886790) As it turns out after a looooong dive down the rabbit hole the content of this task is upsetting the Mail.new function. See the below "fix": https://github.com/bulletproofnetworks/roust/blob/remove_tmail/lib/roust.rb#L551-L552

Feedback will be most welcome :)

[auxesis]

Looks good!

I'll cut a new release.