🚀 go-pugleaf

I like it that I can have a look at a message without marking it as
read when I set vm-preview-lines to a number.  I set it to some number
larger than my screen height (e.g. 80) to see everything I can
possibly see without actually marking it as read.

However, when I insert my INBOX buffer somewhere else while it is
still in preview, only a truncated message gets inserted.  For
example, somebody mailed me a shell script, I want to install it, it
gets truncated and fails mysteriously.  This is annoying.

I propose to let vm-preview-lines==t mean to not truncate the message
at all, but not marking it as read either until I press SPC for the
first time.

-Sebastian