FIX ef3cde, now screen is good & usable

screen does not source your "standard" zsh configuration. Doing so
messed up a bit vim and the terminal under certain circumstances.
This configuration is anyway usable and focused on mail, so it's quite
good anyway
FIX gmail folder mapping
Put sent mail in appropriate folder
getmail accepts arguments
Sidebar virtual mailboxes reordered
nbook: press Ctrl+T to complete addresses
README updated: screen -c is the way to go